# Anvilfield - Plumbing field guides

Backflow repair, DWV venting, hydro tests, water mains, pools, service proof, and chemical dosing.

Hub: https://anvilfield.com/field-guides/plumbing/

Field guides (90):
- https://anvilfield.com/field-guides/plumbing/water-heater-recirculation-sizing/ - A hot water recirculation loop keeps heated water moving from the heater to the far fixtures and back, so hot water arrives fast instead of running cold down the drain. You size the pump to carry the loop's heat loss, size the return smaller than the supply, and balance each riser to hold temperature.
- https://anvilfield.com/field-guides/plumbing/water-damage-restoration-mitigation-iicrc-s500/ - Water damage restoration is drying a wet building out and saving what can be saved after a leak or flood, and it is a race because mold can start in roughly 24 to 48 hours. Extract the standing water fast, build a drying environment, and monitor daily to a dry standard. IICRC S500 and the insurer control.
- https://anvilfield.com/field-guides/plumbing/fire-smoke-damage-restoration-iicrc-s700/ - Fire restoration is cleaning and rebuilding a building after a fire, and it is three problems at once: the char to the structure, the soot that spreads far past the burn, and the odor. Identify the soot type first, because it dictates the cleaning method. IICRC S700, the manufacturer, and the insurer control.
- https://anvilfield.com/field-guides/plumbing/wip-report-over-under-billing/ - A WIP report is a schedule of every open job showing its contract value, costs to date, estimated cost to complete, percent complete, earned revenue, and billings, so you can see whether you are overbilled or underbilled and whether profit is holding. This is general education, not accounting advice, so confirm your accounting method with a construction CPA.
- https://anvilfield.com/field-guides/plumbing/water-well-drilling-pump-systems/ - A water well drills to an aquifer and pumps groundwater up, but the sanitary seal protects what you drink: the casing grouted into the ground stops surface water, septic, and contamination from running down the outside into the aquifer. Site away from contamination, size the pump to depth and yield, test and disinfect, and follow the state well code.
- https://anvilfield.com/field-guides/plumbing/water-wastewater-treatment-plant-systems/ - A water or wastewater treatment plant is a chain of physical, chemical, and biological steps. A drinking-water plant makes raw water safe through coagulation, settling, filtration, and disinfection. A wastewater plant cleans sewage before discharge through screening, primary settling, and a secondary biological stage where billions of microorganisms eat the waste. The EPA, the state, and the certified operator govern.
- https://anvilfield.com/field-guides/plumbing/water-damage-mitigation-structural-drying/ - Water damage mitigation is the fast, documented work of stopping the source, extracting standing water, and drying the structure to a measured dry standard before mold grows. Two facts set the response: the category of the water (clean, gray, or black) and the time, since clean water turns dirty and mold can start in 24 to 48 hours.
- https://anvilfield.com/field-guides/plumbing/warranty-claim-processing-recovery/ - Warranty claim processing is the work of recovering the cost of a failed part, and often a labor allowance, from the manufacturer: register the equipment at install, file the claim with proof, return the defective part on the RGA, and collect the credit. Skip it and you eat defects the manufacturer owed. Terms vary by manufacturer.
- https://anvilfield.com/field-guides/plumbing/trench-excavation-safety-osha/ - Trench safety means protecting workers from a cave-in by sloping the walls back, shoring them, or shielding the crew in a trench box, plus a competent person inspecting the excavation daily. OSHA requires a protective system at 5 ft or deeper, and shallower when a competent person sees a hazard. OSHA and the engineer govern the specifics.
- https://anvilfield.com/field-guides/plumbing/swimming-pool-spa-mechanical-systems/ - A swimming pool or spa mechanical system circulates water through a pump, filter, and heater, then back through the returns, while sanitation keeps it free of pathogens. The two jobs are turnover and chemistry. The main drain can trap and drown a swimmer, so VGB anti-entrapment compliance, NEC 680 bonding, and GFCI are required by law and the health code.
- https://anvilfield.com/field-guides/plumbing/sewage-lift-station-design-pumping/ - A sewage lift station collects wastewater in a wet well and pumps it through a pressurized force main to the gravity sewer when waste cannot reach it by gravity. It runs on duplex pumps, floats, and a high-level alarm, sized to the peak flow and total dynamic head. The engineer, the health code, and the pump manufacturer control the design.
- https://anvilfield.com/field-guides/plumbing/service-callback-warranty-tracking/ - A service callback is a return trip to redo work that should have been right the first time, on your dime. It differs from a warranty claim, where a part failed and the manufacturer owes the cost. Track the callback rate, classify callback versus warranty versus new problem, and claim the failed part. Your policy and the manufacturer terms control.
- https://anvilfield.com/field-guides/plumbing/septic-system-design-installation/ - A septic system treats wastewater where there is no public sewer. The tank settles solids and floats grease, but the real treatment happens in the drainfield soil, where effluent percolates and soil organisms finish it. A soil evaluation comes first and the system is sized to flow. The health code, the soil evaluator, and the AHJ govern the design.
- https://anvilfield.com/field-guides/plumbing/retainage-management-getting-paid/ - Retainage, also called retention, is a percentage of each progress payment the owner or general contractor holds back until the work is accepted, commonly 5 to 10 percent but it varies by contract and state. Because that held-back amount often equals your profit, managing the rate, the cap, and the release decides whether the job actually made money.
- https://anvilfield.com/field-guides/plumbing/reclaimed-water-purple-pipe-systems/ - Reclaimed water is municipally treated wastewater, disinfected to a tertiary standard and delivered as a separate non-potable supply for irrigation, toilet flushing, and cooling, not for drinking. It runs in purple pipe kept separate from potable water, because a cross-connection to drinking water is a public-health event. The adopted code and the water authority control the details.
- https://anvilfield.com/field-guides/plumbing/propane-lp-gas-system-install/ - Propane, or LP-gas, is a fuel stored as a liquid under pressure that feeds homes and equipment where no natural-gas main runs. Propane is heavier than air, so a leak sinks and pools low instead of rising, which drives where you set the tank and the detector. NFPA 58 and the licensed fitter govern the install.
- https://anvilfield.com/field-guides/plumbing/industrial-process-piping-systems/ - Industrial process piping carries chemicals, gases, steam, and process fluids at pressure and temperature inside plants, and it is governed by ASME B31.3, not the plumbing code. The fluid service category, from non-hazardous Category D to highly hazardous Category M, sets how rigorous the welding, examination, and testing must be. The engineer and owner spec control.
- https://anvilfield.com/field-guides/plumbing/fuel-storage-tank-ust-ast-systems/ - A fuel storage tank system holds diesel, gasoline, or heating oil for generators, fleets, retail, or buildings. Underground tanks fall under the EPA UST program in 40 CFR 280, which requires double-wall containment, release detection, spill and overfill prevention, and corrosion protection. Aboveground tanks fall under NFPA 30 and 30A, UL 142, and SPCC. The state program and AHJ control.
- https://anvilfield.com/field-guides/plumbing/flat-rate-pricing-service-price-book/ - Flat-rate pricing quotes the customer one upfront price for the task instead of billing by the hour. The price book is the menu: each task priced from billable labor hours, parts, and markup. It removes clock anxiety, protects margin on slow jobs, and rewards the fast tech. Build the rate on billable, not paid, hours.
- https://anvilfield.com/field-guides/plumbing/fire-sprinkler-system-design-nfpa13/ - A fire sprinkler system is a network of pipe and heat-activated sprinklers that puts water on a fire. Only the sprinkler over the fire opens, not all at once, so it controls the fire while limiting water damage. Design means classifying the hazard, picking the system type, and hydraulically calculating the pipe against the water supply, to NFPA 13.
- https://anvilfield.com/field-guides/plumbing/fire-pump-standpipe-system-design/ - A fire pump boosts water pressure and flow when the public supply cannot meet a sprinkler or standpipe demand. A standpipe carries that water up the building to hose valves on every floor for firefighters. Size the pump to its listed curve under NFPA 20 and NFPA 14; the fire protection engineer and the AHJ control.
- https://anvilfield.com/field-guides/plumbing/contents-pack-out-restoration-inventory/ - A contents pack-out moves a building's belongings off-site so the structure can be dried, cleaned, or rebuilt, but the real work is the inventory: a photographed, tagged, room-by-room record of every item, its condition, and whether it can be saved. That inventory is the chain of custody and the contents claim, not the lifting.
- https://anvilfield.com/field-guides/plumbing/confined-space-entry-permit-required/ - A permit-required confined space is large enough to enter, has limited entry and exit, is not meant for continuous occupancy, and holds a serious hazard such as bad air. Over half of confined-space deaths are would-be rescuers who jumped in untrained. Test the air, ventilate, post an attendant, and never enter to rescue. OSHA and the AHJ govern.
- https://anvilfield.com/field-guides/plumbing/cash-flow-management-forecasting/ - Cash flow management is timing the money coming in against the money going out so payroll always clears. Profit is an opinion on the P&L; cash is the fact in the bank. Build a rolling 13-week forecast, hold a reserve, set up a line of credit before you need it, and watch cash harder than profit.
- https://anvilfield.com/field-guides/plumbing/biohazard-trauma-sewage-cleanup/ - Biohazard remediation cleans and decontaminates scenes fouled by blood, bodily fluids, or sewage, from trauma and unattended deaths to sewage backups and hoarding. The principle is universal precautions: treat every fluid as infectious, protect the worker with PPE, disinfect to the label dwell time, remove porous materials as regulated waste, then verify. OSHA 1910.1030 and state rules govern.
- https://anvilfield.com/field-guides/plumbing/accounts-receivable-collections/ - Accounts receivable is the money customers owe you for work already finished. Collections is the system that turns that owed money into cash fast: invoice the same day, collect at the door on service, set terms in writing, work the aging oldest first, and preserve your lien rights. Cash flow, not profit, decides whether the company survives.
- https://anvilfield.com/field-guides/plumbing/wet-venting-common-vent-design/ - Wet venting is a method where one oversized drain pipe also carries vent air for other fixtures, so a bathroom group needs fewer separate vents. The lavatory drain commonly wet-vents the tub, shower, and water closet through the shared drain. The IPC and UPC write the rules differently, and the adopted code controls what is allowed.
- https://anvilfield.com/field-guides/plumbing/well-pump-pressure-tank-system/ - A well water system pulls groundwater up with a pump, stores it under pressure in a tank, and uses a pressure switch to cycle the pump between a cut-in and cut-out setting, commonly 30/50 or 40/60 psi. The tank's air pre-charge is set about 2 psi below cut-in. Manufacturer data and the adopted well and plumbing code control.
- https://anvilfield.com/field-guides/plumbing/water-treatment-softener-filtration/ - Water treatment conditions a building's incoming water to fix what a water test finds: hardness, iron, low pH, chlorine, sediment, or dissolved solids. A softener removes hardness by ion exchange; filters and reverse osmosis handle the rest. Test first, treat the problem you actually have, and let NSF/ANSI ratings and the plumbing code govern.
- https://anvilfield.com/field-guides/plumbing/water-heater-venting-combustion-air/ - Venting a gas water heater carries the products of combustion, including carbon monoxide, safely outside, while combustion air supplies the oxygen the burner needs to fire clean. Both are life-safety, because a starved or backdrafting appliance spills CO into the room. The manufacturer's instructions, NFPA 54, and the adopted code control.
- https://anvilfield.com/field-guides/plumbing/water-heater-types-tank-tankless-heat-pump/ - A water heater stores or heats domestic hot water by gas, electricity, or a heat pump, in a tank or on demand. Storage tanks cost least up front; tankless and heat pump units cost more but run far cheaper, with UEF often above 3 for heat pumps. Fuel, space, and life-cycle cost drive the choice; manufacturer ratings control the numbers.
- https://anvilfield.com/field-guides/plumbing/water-heater-maintenance-anode-flushing/ - Water heater maintenance is the routine service that keeps a tank from rusting out: flushing sediment, checking or replacing the sacrificial anode rod, and testing the temperature and pressure relief valve. Done yearly, it can roughly double a tank's life. Intervals depend on water quality and the manufacturer's instructions.
- https://anvilfield.com/field-guides/plumbing/water-distribution-system-types-upfeed-downfeed/ - A building water distribution system is the architecture that carries supply water to every fixture at adequate pressure and flow. Upfeed systems push water up from the bottom on street or booster pressure, the common choice for low and mid-rise. Downfeed systems pump to a rooftop tank and feed down by gravity. The adopted plumbing code controls.
- https://anvilfield.com/field-guides/plumbing/trenchless-sewer-repair-pipe-lining-bursting/ - Trenchless sewer repair rehabilitates or replaces a buried sewer with little or no digging. Lining, or CIPP, cures a resin tube inside a sound host pipe to form a pipe within a pipe. Pipe bursting pulls a new HDPE pipe in while shattering the old one. Neither fixes a belly. The camera diagnosis and the sewer authority govern the call.
- https://anvilfield.com/field-guides/plumbing/trap-primer-floor-drain-protection/ - A trap primer is a device that adds a small amount of water to a floor-drain trap, or any seldom-used trap, to keep its water seal from evaporating dry and letting sewer gas into the building. Plumbing codes require trap-seal protection on floor drains that do not get regular use. Verify the method against the adopted code.
- https://anvilfield.com/field-guides/plumbing/thermostatic-mixing-valve-scald-legionella/ - A thermostatic mixing valve blends stored hot water with cold to a safe delivery temperature, resolving the conflict between Legionella and scalding. Store hot, 140 degrees F, to suppress Legionella in the tank, then temper down to 120 degrees F or less at the fixture so it does not burn. The adopted code, ASSE listings, and manufacturer control the settings.
- https://anvilfield.com/field-guides/plumbing/thermal-expansion-tank-closed-system/ - Thermal expansion is the volume increase when water is heated. In a closed plumbing system a check valve, backflow preventer, or pressure reducing valve blocks that expanded water from pushing back to the main, so pressure spikes. An expansion tank with an air cushion absorbs it; the plumbing code and the equipment manufacturer control the sizing.
- https://anvilfield.com/field-guides/plumbing/sump-pump-battery-backup-protection/ - A sump pump battery backup is a second DC pump and a deep-cycle or AGM battery that keep a basement dry when the primary pump fails, usually a power outage during a storm or a burned-out motor. Battery backups run for a finite time; water-powered backups run on city water pressure and require a backflow preventer.
- https://anvilfield.com/field-guides/plumbing/shower-pan-wet-area-waterproofing/ - A shower pan is the waterproof barrier under and around a tiled shower that catches the water tile and grout let through and routes it to the drain. Tile and grout are not waterproof. The membrane is the barrier, built either as a traditional liner over a pre-slope or a modern bonded surface membrane.
- https://anvilfield.com/field-guides/plumbing/sewer-gas-odor-diagnosis-repair/ - Sewer gas odor is the rotten-egg or sewage smell that gets into a building when the barrier between the drainage system and the room fails. The most common cause is a dry trap, so run water down every fixture first. Confirm the source, then smoke test for a hidden leak. Verify any repair against the adopted code.
- https://anvilfield.com/field-guides/plumbing/sewer-camera-cctv-inspection/ - A sewer camera inspection runs a waterproof video camera on a push rod or crawler through a drain or sewer line so you see the inside on a monitor: the roots, the break, the belly, the grease, the blockage. A sonde and above-ground locator then pinpoint the defect's location and depth. NASSCO PACP and the AHJ govern formal coding.
- https://anvilfield.com/field-guides/plumbing/pure-water-ro-di-systems/ - Pure-water systems produce water far cleaner than potable supply by stripping out the dissolved minerals, ions, and organics that tap water carries. Reverse osmosis removes the bulk, deionization polishes the rest, and purity is read as resistivity in megohm-cm. The application standard and the equipment requirements set the grade, not habit.
- https://anvilfield.com/field-guides/plumbing/potable-water-disinfection-flushing-chlorination/ - Potable water disinfection is the chlorination, contact, flushing, and bacteriological testing of a new or repaired water line before anyone drinks from it, so dirt and bacteria from the install do not reach the public. AWWA C651 governs the method; the water authority and health department approve the result.
- https://anvilfield.com/field-guides/plumbing/plumbing-valve-types-selection-isolation/ - A plumbing valve starts, stops, throttles, or protects flow, and you pick it by function: isolation valves like ball and gate run fully open or closed, throttling valves like globe regulate flow, check valves stop backflow, relief valves limit pressure. Match the valve to the media, size, and pressure rating, and let the adopted code and manufacturer control the call.
- https://anvilfield.com/field-guides/plumbing/plumbing-traps-types-trap-seal/ - A plumbing trap is the U-shaped fitting under a fixture that holds a water seal blocking sewer gas, and pests, from entering the building through the drain. Every fixture needs a trap. The seal runs 2 to 4 inches deep, and a vent keeps a draining fixture from siphoning it dry. Verify the depth against the adopted code.
- https://anvilfield.com/field-guides/plumbing/plumbing-special-waste-acid-neutralization/ - Special waste, also called acid or chemical waste, is corrosive or hazardous drainage from labs, hospitals, and industry that would eat a normal drain and cannot enter the sewer untreated. It runs in chemical-resistant pipe, kept separate from the sanitary system, then gets neutralized to a dischargeable pH, commonly near 6 to 9, before it joins the sewer.
- https://anvilfield.com/field-guides/plumbing/plumbing-permit-inspection-process/ - A plumbing permit authorizes the work and the inspections verify it meets code before it is concealed or used. The process runs from permit to underground, rough-in, top-out, and final, with each stage inspected before the next covers it. The adopted code, IPC or UPC, and the local AHJ control what is required.
- https://anvilfield.com/field-guides/plumbing/plumbing-oil-water-separator-sand-interceptor/ - An oil/water separator is a tank that slows the wastewater from garages, vehicle washes, fueling, and shops so petroleum oil floats off and grit settles out before the water reaches the sewer or storm. A sand/oil interceptor adds a grit-settling chamber for the same drains. The plumbing code, the manufacturer's rating, and the discharge permit govern sizing and oil limits.
- https://anvilfield.com/field-guides/plumbing/plumbing-isometric-drawing-riser-diagram-reading/ - A plumbing isometric is a single drawing of the piping shown in 3D on flat paper, with every horizontal run drawn at 30 degrees and every vertical pipe drawn straight up, so the rise, run, and drop read in one view. A flat plan cannot show the vertical. The sheet legend and adopted plumbing code govern.
- https://anvilfield.com/field-guides/plumbing/plumbing-fixtures-types-water-efficiency/ - A plumbing fixture is a device that delivers or receives water at a point of use: toilets, urinals, lavatories, sinks, showers, and drinking fountains. Selection turns on the use and traffic, the water efficiency the code allows, and how the fixture is flushed or supplied. Residential leans on tank fixtures; commercial leans on flushometers.
- https://anvilfield.com/field-guides/plumbing/plumbing-fixture-carriers-supports/ - A plumbing fixture carrier is a concealed steel frame behind the wall that holds a wall-hung toilet, urinal, lavatory, or sink and carries its weight and the user's load down to the floor structure, not the wall or the pipe. Code requires one for wall-hung water closets, and the carrier manufacturer's sheet governs the rough-in.
- https://anvilfield.com/field-guides/plumbing/plumbing-estimating-takeoff/ - A plumbing estimate is the priced takeoff of a job: count the fixtures, measure the pipe and fittings, add material cost, apply labor hours for rough-in and trim, then add overhead and profit to reach the bid. The fixture count drives the rough-in and trim. Your job-cost data and the local market control the numbers.
- https://anvilfield.com/field-guides/plumbing/plumbing-cleanout-requirements-access/ - A plumbing cleanout is a capped access fitting in a drain line that lets you run a rod or jet to clear a blockage without pulling a fixture or digging up pipe. The code requires them at the base of stacks, the building drain and sewer junction, sharp direction changes, and along the run, hedged to IPC or UPC.
- https://anvilfield.com/field-guides/plumbing/pipe-thermal-expansion-movement/ - Thermal expansion is the length change a pipe undergoes as it heats and cools: it grows longer when hot, shorter when cold. Plastics like PEX and CPVC move several times more than copper, and copper more than steel. Restrain that movement and the pipe buckles, ticks, or tears its joints, so long hot runs need loops, offsets, anchors, and guides.
- https://anvilfield.com/field-guides/plumbing/pipe-penetration-firestop-sleeves/ - Firestopping a pipe penetration means sealing the hole and the gap around a pipe where it passes through a fire-rated wall or floor, using a tested, listed system that restores the assembly's fire rating. The system is chosen to match the field condition, not improvised. The UL listing, the adopted code, and the AHJ control it.
- https://anvilfield.com/field-guides/plumbing/pipe-joining-methods-solder-press-solvent/ - Pipe joining is the method that bonds two pieces of pipe into a sealed connection, and the joint is where a piping system fails. Pick the method by the pipe material, the pressure and service, and the adopted code: soldered, brazed, or pressed copper, solvent-welded plastic, threaded or grooved steel, mechanical PEX, or fused polyethylene.
- https://anvilfield.com/field-guides/plumbing/pipe-hangers-supports-seismic-bracing/ - Pipe supports do three jobs: carry the dead weight of the pipe, its contents, and insulation; control sag so drainage holds its slope; and, in seismic zones, brace the pipe against earthquake sway. Spacing comes from the plumbing or mechanical code tables by material and size, and seismic bracing follows ASCE 7 and the engineer.
- https://anvilfield.com/field-guides/plumbing/low-water-pressure-diagnosis-repair/ - Low water pressure is weak force at the fixture, measured in psi. Diagnose it by separating pressure from flow, then narrowing the fault to one fixture or the whole house and to a sudden or gradual onset. Measure static pressure at a hose bibb first; normal is roughly 40 to 80 psi. The adopted plumbing code controls.
- https://anvilfield.com/field-guides/plumbing/lead-service-line-identification-replacement/ - A lead service line is the buried pipe connecting the water main to a building that, on older properties, can be lead and leaches lead into the drinking water. Identify it with a scratch and magnet test, replace it fully rather than partially, and let the EPA Lead and Copper Rule and your utility govern the work.
- https://anvilfield.com/field-guides/plumbing/laboratory-process-vacuum-system/ - A laboratory or process vacuum system is the central setup that pulls vacuum from one or more pumps through piping to inlets at the benches, fume hoods, and process equipment for filtration, aspiration, and evaporation. It is not certified medical vacuum. The adopted code, the process, and the pump manufacturer control the design.
- https://anvilfield.com/field-guides/plumbing/indirect-waste-floor-sink-air-gap/ - An indirect waste is a drain that empties into an open receptor, usually a floor sink, through an air gap rather than connecting directly to the drainage system. The air gap breaks the path so a sewer backup cannot reach food, equipment, or the potable supply. The adopted plumbing code and the AHJ govern.
- https://anvilfield.com/field-guides/plumbing/graywater-rainwater-harvesting-systems/ - Graywater and rainwater harvesting reuse on-site water for non-potable jobs like subsurface irrigation and toilet flushing, which cuts potable demand. Graywater is the gentler wastewater from lavatories, showers, tubs, and laundry, not toilets or kitchens. Rainwater is roof runoff. Keep both fully separate from the potable system, and let the adopted code and the AHJ set the allowed uses.
- https://anvilfield.com/field-guides/plumbing/flushometer-flush-valve-types/ - A flushometer is a valve that delivers a measured, pressurized flush straight from the supply line to a commercial toilet or urinal, with no tank. It uses line pressure for a fast, high-volume flush and recharges in seconds for high-traffic use. It needs adequate flow and pressure, and the valve gpf must match the fixture.
- https://anvilfield.com/field-guides/plumbing/drain-cleaning-jetting-snaking/ - Drain cleaning clears and maintains drain and sewer lines two ways: a cable machine, or snake, punches a hole through a clog to restore flow, and hydro jetting uses high-pressure water to scour the pipe wall clean. Snake to open a line fast; jet to actually clean it. Camera the line first on anything recurring or old.
- https://anvilfield.com/field-guides/plumbing/cross-connection-control-backflow-basics/ - Cross-connection control prevents non-potable water from flowing back into the potable supply. Backflow happens by back-siphonage, from negative supply pressure, or backpressure, from a higher downstream pressure. The protection, an air gap or an RP, DC, PVB, or AVB assembly, is chosen by the degree of hazard and the type of backflow it must stop.
- https://anvilfield.com/field-guides/plumbing/compressed-air-piping-system-design/ - A compressed air system makes, treats, stores, and delivers air to tools and equipment at adequate pressure with clean, dry quality and minimal leaks. Design it around pressure drop and moisture: oversize the piping to hold drop low, dry the air, and never use PVC. The adopted code and equipment requirements control the call.
- https://anvilfield.com/field-guides/plumbing/backwater-valve-sewer-backup-protection/ - A backwater valve is a one-way valve on the building drain or sewer that lets sewage flow out but closes when the public sewer surcharges, blocking sewage from backing up into the lowest fixtures. The plumbing code requires one where fixtures sit below the next upstream manhole cover elevation; the adopted code and AHJ control.
- https://anvilfield.com/field-guides/plumbing/backflow-preventer-assembly-types/ - A backflow preventer assembly is the device that stops non-potable water from reversing into the potable supply at a cross-connection. You pick the type by two facts: the degree of hazard and the backflow mechanism, backsiphonage or backpressure. The RP suits high hazard and both mechanisms, but the local cross-connection program and the AHJ control the final selection.
- https://anvilfield.com/field-guides/plumbing/air-admittance-valve-island-vent/ - An air admittance valve (AAV) is a one-way valve that opens under the negative pressure of a draining fixture to let air into the drain, protecting the trap seal from siphoning, then closes to keep sewer gas out. It vents a fixture without a pipe to the roof, but acceptance varies by code, so the adopted code and AHJ control.
- https://anvilfield.com/field-guides/plumbing/water-supply-pipe-sizing-wsfu/ - Water supply pipe sizing is the calculation that sets each pipe diameter so every fixture gets enough flow and pressure at peak demand without the velocity running high enough to erode the pipe. It works from water supply fixture units converted to a probable demand in gpm, against a pressure budget. The adopted plumbing code, IPC or UPC, controls.
- https://anvilfield.com/field-guides/plumbing/water-pressure-booster-prv-system/ - Building water pressure is managed at two ends: a pressure reducing valve cuts street pressure that runs over the 80 psi code maximum, and a booster pump raises pressure that cannot reach the upper floors. A PRV creates a closed system, so an expansion tank is required. The adopted plumbing code and local water authority control.
- https://anvilfield.com/field-guides/plumbing/water-main-thrust-restraint/ - Thrust restraint holds a pressurized water main where it changes direction or ends, so the line does not blow a joint apart. A pressurized pipe pushes outward at every bend, tee, cap, and reducer with a force near pressure times pipe area. Thrust blocks or restrained joints carry that force into the soil; the project spec governs.
- https://anvilfield.com/field-guides/plumbing/water-heater-sizing-selection/ - Sizing a water heater matches the recovery rate and storage volume to the building's peak-hour hot water demand, so it delivers enough hot water without an oversized, wasteful, or recovery-starved unit. Recovery is the gallons per hour the heater raises across the cold-inlet temperature rise. The stamped design, manufacturer tables, and adopted code control the selection.
- https://anvilfield.com/field-guides/plumbing/water-hammer-arrestor-sizing/ - Water hammer is the pressure surge that hits the piping when fast-moving water is stopped abruptly by a quick-closing valve, banging the pipe and stressing joints and fixtures. A mechanical arrestor with a sealed air charge absorbs it, sized by fixture units to PDI WH-201 and listed to ASSE 1010. The adopted plumbing code controls where one is required.
- https://anvilfield.com/field-guides/plumbing/sump-sewage-ejector-pump-sizing/ - A sewage ejector pump lifts sewage with solids up from below-grade fixtures to the gravity sewer when the drain sits below the sewer line, while a sump pump moves only clear groundwater out of a sump. Size both to the flow and the total dynamic head, and follow the adopted plumbing code, IPC or UPC.
- https://anvilfield.com/field-guides/plumbing/storm-drainage-interior-piping-sizing/ - Interior storm drainage is the piping that carries roof water from the roof drains and scuppers down through the building and out to the storm sewer or daylight, kept entirely separate from the sanitary system. Size the vertical conductors and horizontal storm drains for the design rainfall over the roof area; the adopted plumbing code and AHJ control the numbers.
- https://anvilfield.com/field-guides/plumbing/sanitary-building-sewer-lateral-connection/ - A building sewer is the buried gravity pipe carrying sanitary waste from the building drain, starting 30 in outside the wall, to the public sewer main or a septic tank. Slope it 1/4 in per ft up to 2 in and 1/8 in per ft on 3 in and larger; the plumbing code and the local sewer authority govern it.
- https://anvilfield.com/field-guides/plumbing/plumbing-fixture-rough-in-setting/ - A plumbing rough-in is the drain, vent, and water stub-outs set in the wall and floor to the fixture's dimensions before the surfaces close. Getting it wrong means opening finished work, so measure from the finished wall and floor, not the framing, and the fixture manufacturer's rough-in sheet governs the dimensions.
- https://anvilfield.com/field-guides/plumbing/pipe-insulation-condensation-control/ - Pipe insulation does three jobs: it saves energy on hot pipe, it keeps cold pipe above the dew point so it does not sweat, and it slows heat loss to delay freezing. The energy code sets minimum thickness by pipe size and fluid temperature, but cold lines also need a continuous vapor barrier or they rot from the inside.
- https://anvilfield.com/field-guides/plumbing/pipe-freeze-protection-heat-trace/ - Electric heat trace is a resistance heating cable run along a pipe, under the insulation, that replaces the pipe's heat loss to keep water from freezing, commonly maintaining about 40°F. Insulation alone only delays a freeze. The manufacturer's tables, NEC Article 427, and the project specification govern cable selection and the required ground-fault protection.
- https://anvilfield.com/field-guides/plumbing/pex-copper-cpvc-piping-methods/ - Potable water piping in commercial work runs mostly in three materials: copper, PEX (cross-linked polyethylene), and CPVC (chlorinated PVC). Each has its own joining method, soldered or pressed for copper, expanded or crimped for PEX, solvent-welded for CPVC. No material is best everywhere. Water chemistry, temperature, cost, labor, and the adopted code decide it.
- https://anvilfield.com/field-guides/plumbing/natural-gas-piping-sizing-install/ - Gas pipe sizing sets each section large enough to deliver every appliance its full BTU demand at the right pressure without too much pressure drop. You convert each appliance input from BTU per hour to cubic feet per hour, total the load, then size each section off the NFPA 54 or IFGC tables. The adopted code and gas utility control.
- https://anvilfield.com/field-guides/plumbing/medical-gas-piping-install-certification/ - Medical gas piping is the brazed copper system that carries oxygen, medical air, nitrous oxide, nitrogen, carbon dioxide, and medical vacuum or WAGD to patient outlets in a health care facility. It is governed by NFPA 99, installed only by ASSE-certified personnel, and cannot be used until an independent verifier confirms every outlet delivers the correct gas.
- https://anvilfield.com/field-guides/plumbing/hydrostatic-pressure-test-plumbing/ - A plumbing pressure test proves the drain, waste, and vent piping and the water supply lines hold before they are covered, so a leak shows up at rough-in instead of inside a finished wall. The DWV side is tested with a 10 ft head of water held 15 minutes; the adopted code, IPC or UPC, governs.
- https://anvilfield.com/field-guides/plumbing/grease-interceptor-sizing-maintenance/ - A grease interceptor is a tank or fitting that slows kitchen wastewater so fats, oils, and grease float to the top and food solids settle to the bottom before the water reaches the sewer. It keeps FOG from hardening in the main and backing up the line. Local plumbing code and the municipal FOG program govern sizing and service.
- https://anvilfield.com/field-guides/plumbing/floor-drain-trench-drain-installation/ - A floor drain is a drain set flush in the floor to carry water to the DWV system through a trap; a trench drain is a long channel that catches water across a wide area. Both must keep a wet trap seal, pitch the floor to the inlet, and meet the adopted plumbing code, IPC or UPC.
- https://anvilfield.com/field-guides/plumbing/dwv-venting-pipe-sizing/ - A DWV vent is the pipe that lets air into the drainage system so a draining fixture cannot siphon or blow out the water sitting in its trap. That trap seal is what keeps sewer gas out of the building. Pipe and vent sizing run off drainage fixture units and the adopted plumbing code, IPC or UPC.
- https://anvilfield.com/field-guides/plumbing/domestic-water-service-meter-tap/ - A domestic water service is the pipe and fittings that carry potable water from the public main to the building, through the tap at the main, the corporation stop, the curb stop, and the meter to the building entry. The local water utility and AWWA rules govern the tap through the meter, and the plumbing code governs the line inside.
- https://anvilfield.com/field-guides/plumbing/backflow-assembly-test-procedure/ - A backflow assembly test is an annual field test that confirms the assembly's check valves hold and, on a reduced pressure assembly, the relief valve opens at the right differential, so the cross-connection still protects the potable supply. A certified tester reads the differential with a calibrated gauge, and most jurisdictions require the test yearly.
- https://anvilfield.com/field-guides/plumbing/backflow-failed-test-repair-checklist/ - A failed backflow test means the assembly is no longer holding pressure the way its standard requires, and the failure should produce a diagnosed repair, not just a failed number. Identify which part failed, the relief valve, a check, or the air inlet, flush for debris, rebuild with the matching kit, then retest and pass before return to service.

Calculators (8):
- https://anvilfield.com/calculators/dehumidifier-sizing-calculator/ - Size dehumidification for a water loss: AHAM pints per day = affected volume divided by the class factor.
- https://anvilfield.com/calculators/pipe-flow-velocity-calculator/ - Find water velocity in a pipe from the flow rate: V = 0.4085 x GPM / diameter squared, in feet per second.
- https://anvilfield.com/calculators/pipe-volume-capacity-calculator/ - Find the water a pipe holds from its inside diameter and length: V = pi/4 x diameter squared x length, in gallons.
- https://anvilfield.com/calculators/propane-tank-runtime-calculator/ - Find how long a propane tank lasts: hours = usable tank energy divided by the appliance BTU load.
- https://anvilfield.com/calculators/tank-fill-drain-time-calculator/ - Find how long a tank takes to fill or empty: time = volume divided by flow rate.
- https://anvilfield.com/calculators/tank-volume-cylindrical-calculator/ - Find the gallons in a vertical cylindrical tank from its diameter and height: V = pi/4 x diameter squared x height, in gallons.
- https://anvilfield.com/calculators/thermal-pipe-expansion-calculator/ - Find how much a pipe run grows or shrinks: movement = length x coefficient x temperature change.
- https://anvilfield.com/calculators/water-heating-btu-rate-calculator/ - Find the heat to warm flowing water: BTU/hr = GPM x 500 x the temperature rise, with the kW equivalent.

Readiness checks (10):
- https://anvilfield.com/quizzes/backflow-test-readiness/ - Catches the expired cert, the out-of-cal gauge, or the unbled line that gets a clean assembly reported wrong or the report bounced.
- https://anvilfield.com/quizzes/confined-space-entry-readiness/ - A 2 minute check on whether your confined-space entries are permitted, tested, and rescue-ready, before an atmosphere or a would-be rescuer turns one death into three.
- https://anvilfield.com/quizzes/fire-protection-system-readiness/ - A 2 minute check on whether the sprinklers, fire pump, and standpipes would actually do their job in a fire, before an inspection or an incident finds out for you.
- https://anvilfield.com/quizzes/fire-smoke-restoration-readiness/ - A 2 minute check on whether your fire and smoke cleanup matches the soot type, dries the water first, and kills the odor at the source.
- https://anvilfield.com/quizzes/medical-gas-piping-readiness/ - A 2-minute check that catches the credential, brazing, and verification gaps that keep a system from being used on a patient.
- https://anvilfield.com/quizzes/process-piping-weld-quality-readiness/ - A 2 minute check on whether your process piping is welded, examined, and tested to the fluid service it carries, before a failed weld leaks something hazardous.
- https://anvilfield.com/quizzes/property-loss-emergency-response-readiness/ - A 2 minute check on whether your team can respond to a water, fire, or biohazard loss safely, correctly, and in a way the insurer will pay, before the next call comes in.
- https://anvilfield.com/quizzes/water-damage-restoration-readiness/ - A 2 minute check on whether your water mitigation moves fast enough, dries to standard, and documents the job, before mold sets in or the claim is denied.
- https://anvilfield.com/quizzes/water-heater-install-readiness/ - A 2-minute check that catches the missing demand number, unproven draft, and starved combustion air before you set the unit.
- https://anvilfield.com/quizzes/water-treatment-plant-safety-readiness/ - A 2 minute check on whether your water or wastewater plant work is controlling the gases, confined spaces, biological process, and discharge permit, before a fatality or a violation.

Comparisons (9):
- https://anvilfield.com/compare/grease-interceptor-vs-grease-trap/ - Gravity grease interceptor vs Hydromechanical grease trap
- https://anvilfield.com/compare/heat-pump-vs-gas-water-heater/ - Heat pump water heater vs Gas storage water heater
- https://anvilfield.com/compare/pex-vs-copper-pipe/ - PEX vs Copper pipe
- https://anvilfield.com/compare/septic-vs-sewer/ - Septic system vs Municipal sewer
- https://anvilfield.com/compare/soldered-vs-press-fittings/ - Soldered (sweat) joints vs Press fittings
- https://anvilfield.com/compare/sump-pump-vs-sewage-ejector/ - Sump pump vs Sewage ejector pump
- https://anvilfield.com/compare/tank-vs-tankless-water-heater/ - Tank water heater vs Tankless water heater
- https://anvilfield.com/compare/tankless-gas-vs-electric-water-heater/ - Gas tankless vs Electric tankless
- https://anvilfield.com/compare/trenchless-vs-open-cut-sewer/ - Trenchless (lining or bursting) vs Open-cut dig and replace

Offline field apps (12):
- https://anvilfield.com/subapps/backflow_fix_it_dc/ - Failed-test diagnosis, kit lookup, retest gates, and repair export.
- https://anvilfield.com/subapps/fitupdc/ - Gives WPS bevel angle, root gap, land, and hi-lo limits for weld fit-up plus weld-map exports.
- https://anvilfield.com/subapps/gastrunk/ - Offline app for plumbing, gas fitting, and HVAC install work.
- https://anvilfield.com/subapps/headroom/ - Offline app for well and pump installers, plumbers, and pump-house service techs.
- https://anvilfield.com/subapps/invertchaindc/ - Offline pipe invert grade calculator that chains inverts manhole to manhole and outputs a laser cut sheet.
- https://anvilfield.com/subapps/restroomroutescore/ - Scores restroom routes against APPA levels with photo proof and property-manager audit exports.
- https://anvilfield.com/subapps/salt-cell-service/ - Salt dose, cell cleaning, diagnostics, and PDF service proof for pool route techs at the pad.
- https://anvilfield.com/subapps/sso-clock/ - Starts the sanitary sewer overflow clock, estimates gallons, and exports a clean event packet.
- https://anvilfield.com/subapps/trenchsafe/ - Finds OSHA trench slope, benching, spoil setback, and egress, then captures a signed daily inspection.
- https://anvilfield.com/subapps/ventwright/ - Sizes DWV drains, stacks, and vents under IPC 2021 and exports a permit-ready riser diagram.
- https://anvilfield.com/subapps/watershotdc/ - Records water-main thrust restraint and hydro test results for a clean closeout packet.
- https://anvilfield.com/subapps/wrapbid-dc/ - Pipe insulation takeoff by size with man-hours, material, bid PDF, and pay-app exports.

Printable pack: https://anvilfield.com/field-guides/plumbing/pack/ - every plumbing threshold, spec, and code in one PDF

Field notes (15):
- https://anvilfield.com/blog/plumbing-hydro-test-before-backfill/ - A useful plumbing test packet ties the pipe section, test method, pressure or head, inspection hold point, photos, leaks, corrections, and release decision to the work that is about to disappear.
- https://anvilfield.com/blog/plumbing-fixture-trap-primer-discharge-verification-record-before-odor-complaint-closeout/ - A useful odor closeout packet ties the dry trap, primer type, served drain, activation condition, discharge observation, distribution port, line slope, exception, and recheck together.
- https://anvilfield.com/blog/plumbing-emergency-eyewash-tempering-valve-outlet-temperature-activation-flow-drain-clearance-inspection-tag-and-splash-zone-photo-record-before-safety-walk/ - A field record for documenting emergency eyewash station identity, corrosive-material basis, approach path, tempering valve outlet temperature, activation flow, drain clearance, inspection tag, splash zone, and safety-walk holds.
- https://anvilfield.com/blog/plumbing-commercial-kitchen-grease-interceptor-inlet-and-outlet-baffle-photo-record-before-health-inspection/ - A useful health-inspection packet ties the interceptor tag, fixtures served, access lids, inlet tee, outlet tee, baffle, cleaning status, defects, repairs, photos, and release boundary together.
- https://anvilfield.com/blog/plumbing-exterior-hose-bibb-vacuum-breaker-freeze-shutoff-sleeve-seal-and-drainage-photo-record-before-owner-turnover/ - A plumbing field record for exterior hose bibbs before owner turnover covers vacuum breaker evidence, freeze shutoff location, sleeve seal, drainage, labels, and holds.
- https://anvilfield.com/blog/plumbing-sump-pump-basin-high-water-alarm-float-check-valve-discharge-label-and-backup-power-photo-record-before-turnover/ - Before a sump pump system is turned over, the record should prove basin identity, pump access, float travel, high-water alarm operation, check valve direction, discharge route, backup power status, labels, leak tests, exceptions, retests, and owner handoff.
- https://anvilfield.com/blog/plumbing-water-heater-expansion-tank-support-isolation-valve-relief-discharge-route-pan-drain-and-startup-temperature-photo-record-before-owner-turnover/ - A water heater turnover record for expansion tank support, isolation valve status, relief discharge routing, pan drain evidence, startup temperature, photos, holds, and owner handoff.
- https://anvilfield.com/blog/plumbing-booster-pump-pressure-log-before-low-pressure-complaint-review/ - A useful booster-pump pressure log ties the complaint time, zone served, suction pressure, discharge pressure, setpoint, pump status, VFD speed, alarms, tank precharge, PRV or bypass status, trends, and release decision together.
- https://anvilfield.com/blog/plumbing-mop-sink-faucet-hose-thread-vacuum-breaker-wall-brace-splash-guard-receptor-air-gap-and-health-walk-photo-record-before-turnover/ - A field record for documenting a mop sink before a health walk, including faucet identity, hose-thread vacuum breaker evidence, wall brace support, splash guards, receptor condition, air-gap observations, and release limits.
- https://anvilfield.com/blog/backflow-failed-test-repair-record/ - A failed assembly needs a clean record chain: test result, isolation status, repair action, parts, retest, and the report sent to the water program.
- https://anvilfield.com/blog/plumbing-domestic-hot-water-recirculation-temperature-log-before-balancing-complaint-review/ - A useful hot-water complaint packet ties the reported fixture, loop map, heater and mixing-valve status, pump controls, branch returns, fixture readings, valve settings, corrections, and release boundary together.
- https://anvilfield.com/blog/plumbing-dwv-venting-question-before-rough-in-inspection/ - A useful DWV venting question packet ties the fixture group, trap arm, vent method, approved drawing, code question, photos, RFI or inspector answer, and rough-in release together.
- https://anvilfield.com/blog/plumbing-floor-sink-indirect-waste-air-gap-photo-record-before-health-inspection/ - A useful health-inspection packet ties each food-service drain, floor sink, pipe end, flood-level rim, air-gap photo, cleaning condition, correction, and release limit together.
- https://anvilfield.com/blog/plumbing-water-main-restraint-record-before-pressure-test/ - A useful water-main restraint packet ties the test section, drawings, fittings, thrust points, restrained joints, thrust blocks, temporary caps, valves, hydrants, backfill status, photos, open exceptions, and pressure-test release together before the line is pressurized.
- https://anvilfield.com/blog/plumbing-tempered-water-mixing-valve-outlet-temperature-log-before-fixture-scald-complaint-review/ - A useful scald complaint record ties the mixing valve, outlet temperature, fixture reading, flow condition, thermometer, limit device, check valves, witness, correction, and release boundary together before anyone changes setpoints.