Plumbing
Domestic water service, tap, and meter field guide for plumbers
Coordinate the tap with the utility, set the corp stop and curb stop, run the service below the frost line on a tracer wire, size the meter to the demand, and disinfect before it goes live.
Direct answer
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.
Key takeaways
- Ownership usually splits at the meter: utility governs the main through meter (AWWA rules), the plumbing code (IPC/UPC) governs the line into the building.
- Bury the water service below the local frost line, with deeper cover under driveways and traffic, commonly 18 to 24 in of cover minimum.
- Plastic (PE/HDPE) service lines require a continuous insulated copper tracer wire with accessible terminations, plus warning tape 6 to 12 in above the pipe.
- A service clamp or saddle taps up to 2 in; larger taps go through a tapping sleeve and valve, often a wet tap on a live main.
- Disinfect per AWWA C651: dose commonly 25 mg/L free chlorine, hold about 24 hours, residual above 10 mg/L, then pass a bac-t before connecting.
The water service, and where the utility's line ends and yours begins
A domestic water service is the run of pipe and fittings that brings potable water from the public main in the street into the building. It starts at the tap on the main, goes through the corporation stop at the tap, out to a curb stop and curb box at the property line, through the meter, and into the building at the foundation. Each of those pieces has a name and a job, and most of them are not yours to design. The water utility owns the rules.
The line splits into two halves with different masters. From the main through the meter is the utility's world, governed by the water authority's standard specifications and the AWWA service and meter standards, and on many systems the utility or its contractor makes the tap and owns everything up to and including the meter. From the meter into the building is the customer's service, governed by the adopted plumbing code, the IPC or the UPC. Who owns the pipe between the curb stop and the meter varies by utility, and that line is the first thing to pin down on a job.
Get the division wrong and you build the wrong thing. A plumber who sizes and sets a meter the utility was going to provide, or taps a main the utility insists on tapping itself, has done work that gets torn out. Before anything goes in the ground, you find out who taps, who provides and sets the meter, where the utility's responsibility ends, and what the utility requires for the part that is yours.
Who owns the tap, the meter, and the service line?
Ownership usually splits at the meter, but the exact line varies by water utility, so you confirm it for the address before you bid the work. On most systems the utility owns the main and the tap, owns or controls the corporation stop and the curb stop, and provides and owns the meter. The property owner owns the service line on the building side, and depending on the utility may also own the service pipe from the curb stop to the meter.
This matters for money and for maintenance. The piece you own is the piece you maintain and replace when it leaks, and a service-side leak between the curb stop and the meter on a utility that puts that pipe on the owner is the owner's bill, not the utility's. Lead service line replacement programs have made this division sharper, because a public-side and a private-side replacement are tracked and funded differently, and a partial replacement that leaves half the old line in the ground is its own problem.
The practical move is to get the utility's service standard in hand at the start. It tells you who taps, who provides the meter and the setter, the approved service materials and sizes, the curb stop and box requirements, the backflow the utility requires at the service, and the inspection it will do before it turns the water on. That document governs the part of the job that touches the utility, and the plumbing code governs the rest.
The tap permit and coordinating with the utility
A new water service runs on a tap permit from the water utility, separate from the building plumbing permit, and the utility's process drives the schedule. The permit application asks for the service size, the meter size, the demand or fixture count behind it, and the use, and the utility uses those to set the tap size, the meter, and the connection or capacity fees, which on a large service are a real number that belongs in the bid.
The utility's inspection points are not the same as the plumbing inspector's, and you serve both. The water authority typically inspects or makes the tap, inspects the service line and the curb stop setting, witnesses the pressure test and the disinfection on a larger service, and confirms the meter setting before it energizes the line. The plumbing inspector covers the service inside the building under the adopted code. Two authorities, two checklists, and the line does not get water until both are satisfied.
Lead time is the trap. A tap on a busy main, a road cut permit, traffic control, and a utility crew's schedule can put weeks between the application and the live tap, and the meter itself can be a long-lead item on larger sizes. Pull the tap permit early, find out whether the utility taps or you do, and confirm what the utility wants witnessed, because a tap scheduled late holds up the whole building.
What is a corporation stop?
A corporation stop is the valve and fitting that connects the service line to the water main at the tap, the first shutoff on the service and the point where the customer's water leaves the main. It threads into the main, either directly into the pipe wall or into a tapping saddle clamped around the main, and it carries a valve so the new service can be opened to the line once the tap is made. The plumber and the utility crew both call it the corp, and it is the buried fitting nobody sees again until the service is dug up.
The corp stop is sized and pattern-matched to the main material and the service line it feeds. It takes a specific inlet thread for the tap, commonly the AWWA or CC tapered thread, and a specific outlet to match the service tubing, whether that is a compression or flared joint for copper or a connection for polyethylene with an insert to support the soft tube. AWWA C800 is the standard that governs the corporation stop, the curb stop, and the service fittings between the main and the meter, and the utility's spec calls out the approved makes and patterns.
Where the corp stop sits in the chain is fixed. It is at the main, the curb stop is at the property line, and the meter is downstream of both. The corp is the utility's shutoff at the source, the curb stop is the access shutoff at the street, and the building shutoff inside is yours. Three valves, three jobs, and a service has all three.
Direct tap, saddle tap, and the wet tap on a live main
There are three ways to get a service into a main, and the size and the main material decide which. A direct tap threads the corporation stop straight into the main, cutting the thread into the pipe wall as it goes, and it is used on smaller services into mains that can take a direct thread. A saddle tap clamps a tapping saddle around the main and threads the corp into the saddle, which spreads the load and seals on mains where a direct tap would not hold, and it covers the common small-service sizes.
The wet tap is how you tap a main that is live and under pressure without shutting the system down, and it is the method that earns respect on the job. A tapping sleeve goes around the main, a tapping valve bolts to the sleeve, and a tapping machine mounts to the valve and drives a cutter through the open valve to cut the hole while the main stays in service. The cut coupon is retained on the cutter and pulled back out, the valve is closed, and the machine comes off with the main never depressurized. A common rule is that a service clamp or saddle taps up to 2 in, and a tap larger than that goes through a tapping sleeve and valve.
Who makes the tap is a utility call, not a default. Many systems require the utility's own crew to tap the main, some allow an approved contractor to tap under inspection, and the wet tap on a large main is often a specialty crew with the machine and the experience to do it cleanly. A botched tap, a coupon dropped into the main or a sleeve that weeps, is an expensive mess on a live system, so the work goes to whoever the utility trusts with it. Confirm who taps before you plan the dig.
Where is the curb stop and the curb box?
The curb stop is the utility's shutoff valve out at the property line, sitting in the service line between the main and the meter, and the curb box is the vertical access pipe over it that lets the valve be operated from the surface with a long key. It is the valve the utility uses to turn a property's water on and off at the street, for a shutoff for non-payment, for an emergency, or to isolate the building service from the main without entering the building.
The curb stop sits at or near the property line by the utility's rule, and the curb box brings its operating nut up to grade so a worker can reach it with a curb key without digging. The box has to be plumb over the valve, set to final grade, and clear, because a curb box full of dirt or paved over is a curb stop nobody can find when the water has to go off in a hurry. On systems where the meter is inside the building, the curb stop is the only utility-operable shutoff on the service, which is why the utility cares that it is set right and stays accessible.
On a job, the curb stop and box are set as part of the service line, located off the utility's standard detail, and left at final grade after paving and landscaping are done. The mistake is setting the box to rough grade and walking away, so the lid ends up buried or sticking up where a mower catches it. Set it, then come back and set it to final grade.
The service line: copper, PE, and HDPE, and its size
The service line is the buried pipe from the corporation stop to the building, and the utility's approved materials list decides what you can put in the ground. Type K copper, the heaviest copper tube wall, is the long-standing soft-temper service material, run in a continuous coil with as few buried joints as possible because every buried fitting is a future leak. Polyethylene service tubing, the PE under AWWA C901, and HDPE on systems that allow it, are the common plastic alternatives, run as a continuous coil with no buried joints at all between the corp and the curb stop, joined with fittings that use an insert to support the soft bore. The utility approves the material, the size, and the joint, and that approval is not negotiable.
Size the service to the building's peak demand and the pressure available, not to the size of the main or the size of the nearest fitting on the truck. The demand comes from the same fixture-unit method that sizes the rest of the distribution, run through the demand curve, plus any continuous or process load that does not diversify. The service has to carry that peak demand at a velocity the material tolerates and a friction loss the pressure budget can spend, and the meter and any backflow assembly take their own cut of that pressure before the building sees it. The full sizing method, the WSFU total, the demand curve, the pressure budget, and the velocity limits, is the subject of the water supply pipe sizing guide, and the service is the first segment in that chain.
The cheap mistake is sizing the service tight to save on the tap fee and the pipe. A service one size too small chokes the whole building no matter how generous the pipe behind it, and re-tapping the main to upsize a buried service is a road cut and a new tap, far more than the difference in pipe would have cost. On a service you size for the building you are going to have, with a look at what it might become, because this is the one pipe you cannot easily change later.
How deep does a water service line go?
A water service line is buried below the local frost line so it does not freeze, and the frost depth is local, so the cover that is plenty in a mild climate is nowhere near enough where the ground freezes deep. The plumbing code requires the service below the frost line or otherwise protected from freezing, and a common practice is to carry the pipe a margin below the published frost depth rather than right at it, because frost drives deeper in a hard winter than the average says. Under a driveway or anywhere traffic loads the ground, the cover goes deeper still for physical protection, commonly 18 to 24 in of cover at a minimum on a service.
A plastic service line needs a tracer wire, because PE and HDPE are invisible to the electromagnetic locator every utility uses to find buried pipe. The tracer is a continuous insulated copper wire laid along the pipe with accessible terminations at both ends, so a locator can be clipped on and the line traced and marked years later when someone digs near it. A plastic service with no tracer wire is a line nobody can find, and the day a backhoe is looking for it is the day that matters. Confirm the tracer wire requirement, the wire size, and the termination detail against the adopted code and the utility, because recent code editions have made the tracer wire explicit on nonmetallic buried pipe.
Detectable warning tape is the second layer of protection, a colored ribbon buried in the trench above the pipe, commonly 6 to 12 in above it, so anyone digging hits the tape before the pipe and gets a warning. The tape is not a substitute for the tracer wire. The wire lets you find the line on purpose, the tape warns you off it by accident, and a service gets both. Bed the pipe on clean fill, lay the tracer wire, backfill, set the tape above it, and the line is protected from frost, from the locator's blind spot, and from the next excavator.
The meter and the meter setting
The water meter is the utility's cash register, the device that measures what the building uses, and it sits in the service line where the utility can read it and service it. Where it goes depends on the climate and the utility. In freezing climates the meter usually goes inside the building, just past where the service enters, set on a meter setter or yoke with a shutoff ahead of it. In mild climates the meter often goes outside in a meter box or vault near the property line. Some utilities use an outdoor pit and some prohibit meters belowground entirely, so the setting follows the utility's standard, not the plumber's preference.
The meter setting is the assembly that holds the meter and lets it be changed without cutting pipe. A meter setter, sometimes called a horn or a yoke, is the rigid bracket that spaces the inlet and outlet to the meter's lay length and carries the valves, so a meter can be pulled and a new one dropped in by loosening two couplings. On larger services the setting includes a bypass, a parallel run with its own valve, so the meter can be removed for service or testing without taking the building's water off. The bypass is itself controlled, because an open unmetered bypass is unmetered water, which the utility does not allow without its own valve and seal.
What an inspector and the utility check at the meter is access and orientation. The meter has to be readable, reachable to be changed, set the right direction of flow with the register up, and protected from freezing and from being buried or boxed in. A meter set behind a finished wall or under a deck is a meter the utility cannot read or change, and that becomes the plumber's callback. Set it where it can be reached, to the utility's detail, and confirm the meter is provided by the utility or by you before you order anything.
How do you size a water meter?
You size a water meter to the building's actual flow demand, not to the size of the service pipe, and the framework for it is AWWA M22, the manual on sizing water service lines and meters. The meter is sized to pass the peak demand without too much pressure loss while still registering the low flows the building runs most of the time, and those two ends of the range pull against each other. Sizing a meter to match the pipe is the common shortcut, and it is usually wrong, because the pipe is sized for peak velocity and friction while the meter has to be accurate across the whole flow range the building actually sees.
An oversized meter is the quiet, expensive error. Water meters lose accuracy at the low end of their range, and many will not register very low flows at all, so a meter sized too big sits below its accurate range during the long hours of low demand and under-registers the water that passes through it. That is lost revenue for the utility and a leak-detection blind spot, because a small continuous leak runs under the oversized meter's threshold and never shows on the bill. Utilities have recovered real money right-sizing meters that were set too large years ago, which is the whole argument against rounding the meter up to match the pipe.
The meter types map to the flow pattern. A displacement meter covers the common small services, accurate at low and moderate flows. A turbine meter handles steady high flow but is poor at the low end. A compound meter pairs a turbine for high flow with a small bypass meter for low flow and an automatic valve that diverts the low flows to the small side, which is how a service with both a high peak and long low-flow hours, like many commercial buildings, gets measured accurately across its whole range. Size off the M22 method to the demand, pick the type to the flow pattern, and let the utility's meter rules govern the final call.
Backflow protection at the service
Many services carry a backflow preventer at the entry, the containment assembly that protects the public main from whatever the building might push back into it. This is premises isolation, distinct from the internal backflow protection at each fixture and hazard, and it is the utility's protection of its own system from the building as a whole. Whether the service needs one, and what kind, depends on the hazard the building poses, and the cross-connection control program for the water system makes that call.
The assembly type follows the hazard. A high-hazard premises, where a cross-connection could put a health hazard into the main, gets a reduced pressure principle assembly, the RP, which holds against both backpressure and backsiphonage and dumps to atmosphere if a check fails. A low-hazard premises gets a double check assembly, the DC. The hazard rating, not the plumber's preference, sets which one, and a hospital, a lab, an industrial process, or an irrigation system raises the hazard above what a DC covers. The selection, the standards behind each assembly, and the testing are covered in the backflow assembly test procedure guide.
Two things follow from putting an assembly on the service. It takes a real pressure loss, often several psi and more on an RP, which comes straight off the pressure budget that sizes the building's pipe, so the service backflow has to be in the budget before the distribution is sized. And it has to be tested at installation and at least annually after, by a certified tester, on the utility's clock, so the assembly is set where it can be tested and serviced, not buried in a tight closet. Plan the location for the test, not just for the connection.
The building entry, the seal, and the main shutoff
The service comes into the building either up through the floor slab or in through the foundation wall, and either way it goes through a sleeve that protects the pipe and seals the opening. A pipe cast or cored straight into concrete with no sleeve is a pipe that gets abraded as the building settles and a path for water and soil gas to follow the pipe into the building. The sleeve carries the pipe through the wall or slab, and the annular space between the pipe and the sleeve gets sealed against water and, on a slab, against soil gas, with the seal detail following the code and the conditions.
Below grade, where the service enters through a foundation wall under the water table, the seal is a waterproofing detail as much as a plumbing one, because that penetration is a place hydrostatic pressure will push water into the basement if it is not sealed right. A mechanical link-seal or a cast sleeve with a proper seal handles the moving joint between a rigid wall and a service that has to be free to settle slightly. The detail belongs on the drawings, and on a wet site it gets done with the waterproofing, not patched after the fact.
Inside, just past the entry, the service gets the building's main shutoff, the valve that takes the whole building's water off in one move, ahead of the meter on systems where the meter is inside or just downstream of it. A full-port ball valve is the common choice, a quarter turn to off, set where it can be found and reached in an emergency rather than behind storage in a far corner. Everyone who works in that building should be able to find that valve in the dark, because the day it matters, water is already running where it should not be.
Does the building need a separate fire and irrigation tap?
A building with a fire sprinkler system usually has a separate fire service, tapped and metered apart from the domestic service, because the two have different demands, different metering, and different backflow rules. The fire service sits idle at full pressure and then dumps a large flow on a fire, a pattern the domestic meter is not built to measure, so it gets its own tap, its own larger line, and often a detector-type meter that registers only the small leak or test flow while passing the fire flow unmetered. On a building of any size the fire service is its own design, coordinated with the fire protection engineer and the utility.
Backflow on the fire line follows the fire hazard, not the domestic one. A fire system holds stagnant water, sometimes with antifreeze or foam additives, and the code protects the main from it with a double check or a reduced pressure assembly, in the detector versions, a DCDA or RPDA, that carry a metered bypass to catch a leak or an unauthorized draw. Which one depends on what is in the fire system, with additives pushing it to the reduced pressure detector assembly.
Irrigation is the other common separate service or sub-meter. A separate irrigation meter lets the utility bill irrigation water without sewer charges on it, since it does not return to the sewer, and it isolates a high-hazard cross-connection, because an irrigation system in contact with soil, fertilizer, and standing water is exactly the hazard a service backflow assembly exists to contain. An irrigation tap or sub-meter gets its own backflow protection sized to that hazard, commonly an RP or a pressure vacuum breaker on the irrigation side, per the local rules.
Static pressure at the service and the PRV
The static pressure the service delivers is whatever the utility holds at the main minus the elevation lift to the building, and it sets the starting point for the whole distribution. You build the sizing on the minimum daily service pressure the utility guarantees, not the peak it sometimes reads, because the building has to work on the worst day, not the best one. Get the guaranteed low from the water authority in writing, because a service sized off an optimistic pressure runs weak at the far fixture every afternoon when the system pressure sags.
On the high side, the code caps the static pressure at the building, commonly 80 psi, and above that cap a pressure-reducing valve goes on the service to knock it down. High street pressure is common on low ground near a pumping station or at the bottom of a pressure zone, and water over the cap wears fittings, worsens water hammer, and drives the thermal expansion problem on the hot side. When the static at the service runs over the cap, a PRV on the building side of the meter brings it back into range, and a building tall enough to need it also needs the pressure zoned up its height, which is its own design.
When the service pressure is too low to serve the building, the answer is a booster, and that is a designed system, not a part you bolt on. A building on a low service pressure, a tall building where elevation eats the budget, or a building with a high peak demand can outrun what the street can give, and a booster pump package makes up the difference, sized to the peak demand at the head the building needs. The booster, the PRV, and the pressure zones are covered by topic in the booster and pressure-zone material, and they all start from the same number: the guaranteed service pressure at the meter.
How do you pressure test and disinfect a new water service?
A new water service is pressure tested and then disinfected before it is connected to the building and put in service, because a buried line full of trench water, soil, and construction debris is a contamination path straight into the potable system. The pressure test comes first, a hydrostatic test that holds the line at a test pressure for a set time and confirms the leakage stays under the allowable rate, proving the joints and the pipe hold before anything is buried for good. The utility sets the test pressure, the duration, and the allowable leakage, and on a larger service it witnesses the test.
Disinfection follows the AWWA C651 framework, the standard for disinfecting water mains, which the utility applies to new mains and service lines on its system. The line is charged with chlorinated water, commonly dosed to at least 25 mg/L of free chlorine, and held in the pipe for a holding period, commonly at least 24 hours, longer in cold water, after which the free chlorine residual has to still read above a set minimum, commonly 10 mg/L, proving the chlorine was strong enough and held long enough to do the job. The numbers come from the standard and the utility's spec, so confirm them against the edition and the program before you dose.
Bacteriological clearance is what actually releases the line. After the holding period the chlorinated water is flushed out to the sewer or to where it can be dechlorinated, and a bacteriological sample, the bac-t, is pulled and sent to the lab, with the line kept isolated from the active system until the bac-t comes back clean. A failed bac-t means you disinfect and sample again, not connect and hope. The line does not get tied into the building and the curb stop does not get turned on until the pressure test passed, the disinfection held its residual, and the bac-t cleared. Skip a step and you own whatever comes out of the tap.
Large commercial and data center service
On large commercial work the service still follows the same chain, the tap, the corp or the tapping sleeve, the service line, the meter, and the backflow, but the sizes grow, the tap goes through a tapping sleeve and valve, and the meter becomes a compound or a large turbine with a bypass for service. The demand mix also shifts, because a large building carries continuous and process loads that do not diversify the way fixtures do, a commercial kitchen, a laundry, cooling-tower makeup, or an irrigation tap, and those get added to the diversified fixture demand rather than run through the curve.
A data center is the sharp case. The people load is small, but the makeup water for evaporative or adiabatic cooling and for humidification can dwarf the restroom demand and runs closer to continuous, so sizing the service off the restroom fixture count alone badly undersizes it. The mechanical makeup is often the governing demand, it gets its own metering and its own backflow protection so the cooling system cannot push treated or contaminated water back into the potable supply, and the domestic service is designed around both the small fixture load and the large steady mechanical load together.
Across the large work two things hold. The bigger and more critical the service, the more it is an engineered, stamped design run off the project documents and the utility's standards, with the fixture-unit method as the framework for the fixture portion and the continuous loads added on top from their rated flows. And redundancy enters the picture, because a critical building may need two services off separate mains, separately tapped and metered, so a single main break or a single tap failure does not take the whole building down.
The owner-side maintenance
Once the service is live, the owner inherits a short list of things that have to be maintained, and the install is where you set them up to be maintainable or set up a future headache. The service-side backflow assembly is the big one, because it is a legal annual test on the utility's clock, and a building owner who treats the test notice as junk mail loses water service until a passing test is on file. Set the assembly where a tester can reach it and isolate it, and the annual test is routine instead of a fight.
The valves are the next thing. The building main shutoff, the meter valves, and the curb stop all have to work when they are finally needed, which is often years after they were last touched, and a valve that has sat untouched can be the one that will not close in the emergency. The curb box has to stay accessible and not get paved or buried, the main shutoff has to stay reachable and not get walled in by a later remodel, and the owner who exercises the main valve once in a while is the owner whose valve closes when a pipe lets go.
The meter itself is the utility's to maintain and replace, but the owner owns keeping it accessible and protected from freezing, and a meter that gets boxed in by a later finish or left to freeze becomes the owner's problem the day it fails. The plumbing side of all of this is simple: hand the owner a service where every valve, the meter, and the backflow can be reached and worked on, and the maintenance the owner inherits is maintenance they can actually do.
What to document
A service that nobody recorded is a service the next person has to dig up to understand, and the record is what answers where the line runs, what it is made of, how big the tap and meter are, and what protects the main. The record is also what the utility and the inspector sign off on, and it is what a locator and the tracer wire work from years later when someone needs to find the line.
Capture the tap location and size, the service line material and size, the burial depth and the tracer wire and tape, the curb stop location, the meter size and type and serial, the backflow assembly type and serial, the static pressure the service delivers, and the results of the pressure test, the disinfection, and the bac-t. Record which utility standard and which code edition the work was done to, because the sizes and the criteria only mean something tied to the rules that produced them. The as-built that shows where the buried line actually runs is worth more than any other page in the file the first time a backhoe goes looking for it.
| Field to record | Why it matters |
|---|---|
| Tap location, size, and method | Where the service meets the main and how it was tapped |
| Service line material and size | Drives the demand it carries and what gets replaced later |
| Burial depth, tracer wire, warning tape | Proves frost protection and lets the buried line be located |
| Curb stop and curb box location | The utility's shutoff has to be findable at the street |
| Meter size, type, and serial | Ties the register to the building and the demand it was sized to |
| Backflow assembly type and serial | Sets the annual test and proves the main is protected |
| Static pressure delivered | The starting point for the whole distribution sizing |
| Pressure test, disinfection, bac-t results | Proves the line was tight and clean before it went live |
| Utility standard and code edition | The sizes and criteria only mean something against the rules used |
Common mistakes
- Sizing the service to the main or the nearest fitting instead of the building's peak demand, so it chokes the building and a re-tap is the only fix.
- Running a plastic service with no tracer wire, leaving a buried line the locator cannot find.
- Burying the service above the local frost line or skipping the deeper cover under a driveway, so it freezes or gets crushed.
- Oversizing the meter to match the pipe, so it under-registers low flows, loses revenue, and hides small leaks.
- Leaving the service with no backflow protection, or the wrong type for the hazard, so the building can push back into the main.
- Connecting and turning on the service before the pressure test, disinfection, and bac-t have cleared.
- Sealing the building entry poorly, so the penetration leaks water or soil gas into the building below grade.
- Setting the curb box and the main shutoff where they cannot be found or reached when the water has to go off.
- Tapping the main, or providing and setting the meter, when the utility was going to do it, so the work gets torn out.
Field checklist
Want this checklist to run itself on every job — with photo proof and a signed record crews can hand the customer? That's FieldOS.
Standards and references
The service splits its governing rules between the water utility and the plumbing code, and the adopted edition with local amendments controls. From the main through the meter, the water authority's standard specifications and the AWWA standards govern. AWWA C800 covers the underground service line valves and fittings, the corporation stop, the curb stop, and the service saddles between the main and the meter. AWWA C901 covers polyethylene service tubing, AWWA M22 is the manual for sizing the service line and the meter, and the AWWA C700-series standards cover the meters by type, the displacement, turbine, and compound meters. The utility's own service standard is the document that pulls these together for the system you are tapping.
The disinfection and the new-main work follow AWWA C651, disinfecting water mains, which the utility applies to new services and mains, with its dose, holding period, residual, and bacteriological clearance. The hydrostatic pressure test and its allowable leakage come from the utility's spec and the AWWA pipe installation standards for the main material. The exact criteria and the witnessed steps are the utility's call, so confirm them against the edition and the program before you test or dose, and never cite a number from memory across editions.
From the meter into the building, the adopted plumbing code governs, the IPC published by the ICC or the UPC published by IAPMO, covering the building service, the minimum sizes, the freeze protection, the main shutoff, and the backflow protection at the service. The cross-connection control program of the water purveyor sets the service backflow requirement and the annual test, covered in the backflow assembly test procedure guide, and the distribution sizing behind the meter is covered in the water supply pipe sizing guide. Cite the standard that controls the point, confirm it against the utility and the AHJ, and let the project documents and the utility's standard override any rule of thumb here.
Units, terms, and conversions
The water service carries a few units and a few names for the same part, and the same fitting can read differently across a utility detail, a code section, and a manufacturer's catalog.
Pipe and tap are sized by nominal diameter in inches. Pressure is in psi, with the lift to elevation at 0.433 psi per foot of height, read the other way as one psi for every 2.31 ft of head. Flow demand is in gallons per minute, gpm, off the fixture-unit method and the demand curve, and metric work uses liters per second. Copper service tube is specified by type, with Type K the heaviest wall used for buried service, and plastic service by material and pressure class, PE and HDPE. Chlorine dose and residual in disinfection are in milligrams per liter, mg/L, of free chlorine.
- Corporation stop
- The valve and fitting that taps the service into the main, threaded into the pipe or a tapping saddle (AWWA C800), the first shutoff on the service
- Curb stop and curb box
- The utility's shutoff valve at the property line and the access pipe over it operated from the surface with a curb key
- Tapping saddle / sleeve
- A saddle clamps the corp to the main for small taps; a tapping sleeve and valve carries a wet tap larger than about 2 in on a live main
- Wet tap
- Tapping a main under pressure with a sleeve, valve, and tapping machine, cutting and retaining a coupon without taking the main out of service
- Meter setter / horn
- The rigid bracket or yoke that holds the meter to its lay length and carries the valves, so a meter can be changed without cutting pipe
- Containment backflow
- The backflow assembly at the service entry that protects the main from the whole building, an RP for high hazard or a DC for low hazard
- Tracer wire
- A continuous insulated copper wire laid along a plastic service so the buried line can be found with a locator, with accessible terminations
- Bac-t
- The bacteriological test that clears a disinfected new service before it is connected, after the pressure test and the chlorine holding period
FAQ
What is a corporation stop?
A corporation stop is the valve and fitting that taps a water service into the main, the first shutoff on the service. It threads into the main directly or into a tapping saddle clamped around it. AWWA C800 governs the corp, the curb stop, and the service fittings. The utility's standard sets the approved pattern.
How deep does a water service line go?
A water service is buried below the local frost line so it does not freeze, deeper than the published frost depth as a margin, with more cover under driveways and traffic, commonly 18 to 24 in minimum there. Confirm the frost depth and cover against the adopted code and the utility, since frost depth is local.
How do you size a water meter?
Size a water meter to the building's flow demand off the AWWA M22 method, not to the service pipe size. The meter must pass peak flow while still registering low flows accurately. Pick the type to the flow pattern, displacement, turbine, or compound. The utility's meter rules govern the final call.
Does a water service need a backflow preventer?
Many do. A service-side containment assembly protects the main from the building, with the type set by the hazard: a reduced pressure assembly for high hazard, a double check for low hazard. The cross-connection control program decides whether the service needs one. It is tested at install and at least annually after.
Who owns the water service line, the utility or the owner?
Ownership usually splits at the meter, but the exact line varies by utility. The utility commonly owns the main, the tap, and the meter, and the owner owns the service on the building side, sometimes back to the curb stop. Confirm the division for the address, because it sets who maintains and replaces the pipe.
What is the difference between a corporation stop and a curb stop?
A corporation stop is the shutoff at the main where the service taps in, usually buried and rarely touched. A curb stop is the utility's shutoff at the property line, set in a curb box so it can be operated from the surface with a key. The corp is at the source, the curb stop at the street.
Can a water meter be too big?
Yes, and an oversized meter is a costly error. Meters lose accuracy at the low end and may not register very low flows at all, so a too-large meter under-registers the building's everyday flow, loses the utility revenue, and hides small continuous leaks. Size the meter to the demand, not to the pipe, off AWWA M22.
Do you have to disinfect a new water service?
Yes. A new service is pressure tested, then disinfected to the AWWA C651 framework, charged with chlorinated water and held to hold a residual, then flushed and cleared by a bacteriological test before it connects. The line stays isolated until the bac-t passes. Confirm the dose, holding time, and criteria with the utility.
How do you tap a water main without shutting it down?
You wet tap it. A tapping sleeve goes around the live main, a tapping valve bolts to the sleeve, and a tapping machine cuts through the open valve while the main stays pressurized, retaining the cut coupon. A saddle or clamp taps up to about 2 in; larger taps use a sleeve and valve. Many utilities tap their own mains.
Does a water service over 80 psi need a pressure-reducing valve?
Yes. The plumbing code caps static pressure at the building, commonly 80 psi, and above that a pressure-reducing valve goes on the service to bring it down. High pressure wears fittings, worsens water hammer, and drives hot-side thermal expansion. Verify the cap and the PRV requirement against the adopted code and the utility.
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Codes cited in this guide
This guide is written and reviewed against the published standards below. Always confirm the current adopted edition with the authority having jurisdiction.