Galvanized pipe corrosion survey field guide for a building repipe

What does a galvanized pipe corrosion survey deliver?

Give cold supply, hot supply and hot-water return separate identities within the five survey records. Each replacement recommendation must identify its segment, supporting evidence and proposed tie-ins.

Establish what the pipe actually is. [ASTM A53/A53M-24](https://store.astm.org/a0053_a0053m-24.html) covers zinc-coated steel pipe; GI commonly identifies this galvanized steel in project records. A magnet, threaded fitting and silver-gray surface are screening clues. Verify accessible pipe and label concealed material unverified until records or an opening resolve it.

Which records belong in the survey authorization?

Collect original and revised risers, permits, fixture schedules, repairs, invoices, utility service-line history and water-quality reports. Anvilfield uses a selected 36-month repair lookback, retaining dates and missing-record periods. Record treatment changes, occupancy restrictions and the locally adopted plumbing and electrical editions.

Authorize openings, outages, sample ownership, laboratory tasks and restoration before cutting. This guide addresses building potable-water distribution and its service interface. Fire protection, hydronic heating, process water and sanitary drainage require their own procedures; [sewer camera inspection and locating](/field-guides/plumbing/sewer-camera-cctv-inspection/) supplies a separate drainage workflow.

Resolve suspect insulation and painted finishes before opening shafts or preparing UT surfaces. OSHA [29 CFR 1926.1101(k)(2)](https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1101) requires building owners to identify asbestos-containing or presumed asbestos-containing material before covered work; [29 CFR 1926.62(d)](https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.62) requires employers to determine worker lead exposure. Carry the resulting access controls into the survey scope.

Choose replacement materials after defining the service duties, using the [PPR vs GI vs copper pipe guide](/field-guides/plumbing/ppr-vs-gi-vs-copper-pipe/).

How do you build a segment condition map?

Assign stable IDs to each main, riser, branch and return. Split a segment when material, diameter, installation age, pressure zone, service or isolation boundary changes. Reconcile [plumbing riser diagrams](/field-guides/plumbing/plumbing-isometric-drawing-riser-diagram-reading/) with the route observed on site; a drawing records an intended route until field evidence confirms it.

Record length and its basis, nominal size, verified dimensions, temperature, rooms served, valves, access class and photographs. Attach leak IDs, gauge points, cutouts and ultrasonic thickness (UT) stations. Use observed, record-supported and unverified as explicit evidence states, with a separate action priority. An empty condition field means missing evidence.

The worked survey is an Anvilfield estimate for a three-story, 12-unit building with four hot/cold riser pairs. Each 100 ft pair comprises 50 ft cold and 50 ft hot, including offsets. Split R01-C/H through R04-C/H into eight field IDs, and split the hot/cold branches too; grouped quantities below are estimating allowances. P0/P1 bracket the cold-main test route; P2/P3 bracket the hot-main route downstream of separately measured heater/device losses.

Table 1. Segment condition map and evidence assignments

Which exposure differences change sampling priority?

Record source and treatment history, available pH, alkalinity and disinfectant information, supply/return temperatures, stagnation, dissimilar-metal transitions and exterior wetting. Use these as Anvilfield sampling groups. [EPA's August 2022 inventory guidance](https://www.epa.gov/system/files/documents/2022-08/Inventory%20Guidance_August%202022_508%20compliant.pdf) supports tracing service-line material history; [CDC potable-water guidance](https://www.cdc.gov/control-legionella/php/toolkit/potable-water-systems-module.html) addresses stagnation, temperature and disinfectant control. A utility annual report describes supplied water; it does not measure water after stagnation in a particular riser.

Include wet shafts, damaged insulation, unheated spaces and concealed repairs in the access plan. Link every opening to floor, room, orientation and flow direction.

Is the problem tuberculation or low supply pressure?

Tuberculation is corrosion-product growth inside the pipe that roughens or obstructs its waterway. Locate excess loss while water flows: static pressure can equalize through a restricted passage. Begin with [low water pressure diagnosis](/field-guides/plumbing/low-water-pressure-diagnosis-repair/) to clear fixture, valve and source faults before assigning a pipe defect.

Measure upstream and downstream pressures simultaneously at recorded flow and gauge-centerline elevations. Bracket the service entry, PRV/backflow equipment, riser base and remote outlet. Log pump state, valve positions, time, temperature and background demand. Anvilfield selects 5 and 10 gpm as test points where essential service permits. Stabilize each draw, read both gauges together and repeat the lower-flow point to reveal changing supply conditions. Meter total flow through the tested segment, including other active outlets; actual demand comes from the approved [water supply sizing and WSFU calculation](/field-guides/plumbing/water-supply-pipe-sizing-wsfu/).

Table 2. Competing causes and the separating measurement

How do elevation and instrument error change the result?

The [Hydraulic Institute formula reference, Version 1](https://www.pumps.org/wp-content/uploads/2025/02/PSC-Exam-Formula-Reference-Sheet.pdf) gives 2.31 ft of water per psi at specific gravity 1, equivalent to approximately 0.433 psi/ft. For an upward route with equal endpoint velocities and no intervening pump, subtract elevation pressure from the measured differential to obtain combined pipe, fitting and device loss. Subtract measured device loss before assigning the remainder to pipe.

Use [booster and PRV diagnosis](/field-guides/plumbing/water-pressure-booster-prv-system/) for those equipment boundaries and [hydrostatic head](/field-guides/glossary/hydrostatic-head/) for the elevation relationship. Different endpoint diameters or flows require velocity-head accounting; an intervening pump requires its added head. Put pressure taps upstream of an open discharge because the free outlet itself cannot supply a fixture-pressure reading.

Anvilfield selects two 0-100 psi gauges specified at ±1% of full scale: each contributes ±1 psi, giving up to ±2 psi differential error before flow and elevation error. A 1 psi apparent excess cannot settle replacement with that setup. Compare gauges on a common manifold and use suitable differential equipment for small losses.

Keep gauge IDs, accuracy checks and demand records; repeat through relevant pump cycles and peak use. The [2025 Plumbing Code of New York State §604.8](https://dos.ny.gov/nys-plumbing-code-noa-7182025) generally requires pressure reduction above 80 psi static to no more than 80 psi; exceptions cover sill-cock/outside-hydrant services and main risers reduced to that limit at individual fixtures. This local static limit is separate from endpoint flowing requirements.

How much pressure loss can a restricted bore create?

Anvilfield estimates that reducing a 1 in Schedule 40 pipe's 1.049 in bore to 20 mm raises straight-pipe friction loss from 3.60 to 14.56 psi per 100 ft at 10 gpm and Hazen-Williams C = 120, using [Wheatland's published dimensions](https://www.wheatland.com/wp-content/uploads/2017/12/Standard-Pipe-Brochure-2.pdf) and [EPA's EPANET 2.2 equations](https://raw.githubusercontent.com/USEPA/EPANET2.2/master/User_Manual/EPANET_User%27s_Manual_2.2.0.pdf). That is a 4.04-fold increase at unchanged length, flow and coefficient.

This 100 ft, 1 in comparison route is separate from the map's 1.5 in mains. Calculate with inside diameter; nominal size is not bore. EPA lists C = 120 for new galvanized iron; the C = 80 case below is Anvilfield's selected roughness sensitivity. Irregular deposits and fittings require field checks against the paired readings.

Table 3. Worked pressure-loss comparison

What does that loss do to a remote fixture?

With Anvilfield's selected 60 psi flowing inlet pressure, 30 ft rise and separate 5 psi device/fitting allowance, 42.01 psi remains before straight-pipe friction. The three endpoint estimates are 38.41, 27.45 and 11.16 psi. Against a selected 20 psi endpoint design requirement, the margins are 18.41 psi, 7.45 psi and a shortfall of 8.84 psi.

The example uses equal-velocity endpoint taps, no pump between them and 10 gpm throughout the route. A branched network needs segment-specific flows. New York's 2025 §604.3 requires the peak-demand capacities in its fixture table; manufacturer instructions govern fixtures absent from that table. Apply the adopted design requirement for the actual outlet.

Method, November 5, 2026: divide flow by circular area for velocity; subtract elevation, devices and pipe [friction head](/field-guides/glossary/h-friction/) from flowing inlet pressure. Anvilfield estimates use the linked EPA, Wheatland and Hydraulic Institute sources, selected bore/pressure inputs and 0.433 psi per foot.

Use L and d in feet, Q in cubic feet per second and dimensionless C: hL = 4.727 × L × Q^1.852 / (C^1.852 × d^4.871). With pressures in psi and rise in feet: Pout = Pin - 0.433 × rise - Pdevices - 0.433 × hL.

How does the calculation change the scope?

The roughened 20 mm case falls 8.84 psi short of the selected endpoint requirement. Assign that path hydraulic priority C in the severity table and size its replacement for the required demand. The smoother 20 mm case meets the same pressure target, so restriction alone does not settle replacement; use its separate joint, wall and water-quality findings. In both cases, locate usable tie-ins before defining the replacement length.

What is a practical galvanized pipe sampling plan?

Anvilfield estimates eight removed-pipe samples and 24 UT stations for the mapped base survey. Select distinct cold, hot, main, riser and branch conditions, with upper/lower, complaint/comparison and repaired/original locations. Add a separate sampling group for every additional return loop, pressure zone, material age or failure pattern.

Take cutouts at authorized renewal points during planned isolation. Include a threaded end or fitting when joint deterioration is the question. Agree sample dimensions, preservation and requested tests with the laboratory before removal. One accessible nipple cannot classify an entire riser.

Table 4. Coupon and thickness sampling matrix

The allocation is four main, 16 riser and four branch stations. At each station, Anvilfield's screening plan takes four clock positions at three axial rings: 12 readings per station and 288 baseline readings. These sparse spots require validated scanning around defects and proposed retention boundaries before assigning a minimum to an area.

When should sampling expand or cutting stop?

Expand at a new exposure group, conflicting cutout/UT results, unresolved no-read, damaged proposed tie-in or failure outside the sampled group. Add authorized upstream and downstream exposures around a disputed boundary until usable tie-ins are established. Where full riser removal is already selected, focus further openings on tie-ins, temporary service and evidence that changes the work.

Stop opening when isolation cannot be proved, essential water cannot be maintained, electrical preparation is incomplete or restoration exceeds authorization. Mark the affected segment unverified and price enabling work. An agreed sample allowance never overrides an unresolved pressure boundary.

What does the laboratory receive?

Label segment, floor/room, orientation, upstream end, service, removal date and nominal size; photograph with a scale and package samples separately. Preserve the as-found waterway before cleaning, then record cleaned steel, pits and thread roots separately. Distinguish a removed pipe sample from a newly exposed corrosion-monitoring coupon: the latter cannot reconstruct an old pipe's deepest pit.

Water metals, deposit composition and remaining metal answer different questions. Follow the selected laboratory protocol for water preservation and chain of custody. A coupon/deposit assay is not a drinking-water result.

What can thickness testing prove, and what requires replacement?

[ASTM E797/E797M-21](https://store.astm.org/e0797_e0797m-21.html) describes local ultrasonic thickness measurement, with limitations for curved and nonparallel surfaces; its public scope supplies neither a building sampling count nor a universal retirement wall thickness for galvanized water pipe. Select retention criteria around pressure-boundary condition, joints, demand, failure consequences and measured uncertainty.

Validate the gauge/probe combination for actual curvature, surface and temperature, with calibration checks and a mechanically measured cutout where available. Prepare only the surface needed for coupling under the approved procedure. Aggressive grinding can breach a weakened live wall. Retain raw readings, minima and no-read locations; an absent echo requires another method.

Table 5. Measurement-method differences

The named probe limits come from [Evident's dual-element corrosion-gauging note](https://ims.evidentscientific.com/en/applications/corrosion-gaging-dual-element-transducers); coating limits come from its [coating tutorial](https://ims.evidentscientific.com/en/learn/ndt-tutorials/thickness-gauge/coatings), both checked November 5, 2026. Metallic zinc is distinct from nonmetallic paint; document how coating and surface preparation affect the reported steel thickness. Gauge, probe, couplant and method limits all apply; the most restrictive controls.

Evident recommends data spacing no greater than half the probe diameter for pit coverage. Its 7.2 mm D792 face gives approximately 3.6 mm spacing under that guidance; four clock spots are screening, not pit mapping. The operator must validate actual coverage for the surface being accepted.

Can a barrel reading clear a threaded connection?

A barrel reading cannot establish the hidden thread-root condition inside a fitting. Examine removed joints and the actual proposed tie-in. Neither an averaged wall percentage nor pipe age supplies a universal replacement trigger, and nominal new wall minus one old reading is not a measured annual corrosion rate.

Anvilfield recommends annual review of the retained-segment register and review after a leak, major pressure/treatment change or significant opening. Repeat mapped measurements where a trend changes scope, using comparable points and methods with uncertainty recorded. Keep that owner planning interval separate from ASTM requirements.

Can galvanized interior pipe retain lead after service replacement?

The [DCWASA-commissioned HDR study of September 2009](https://archive.epa.gov/dclead/web/pdf/galvanized%20project%20report.pdf) evaluated 62 residential profiles at 21 homes and found that old galvanized interior plumbing can retain and release lead after upstream lead service-line replacement. Carry the former upstream material into the interior survey even when the visible entry is now copper.

Obtain utility ownership and material records through the [lead service line identification and replacement](/field-guides/plumbing/lead-service-line-identification-replacement/) workflow. EPA's [October 2024 LCRI fact sheet](https://www.epa.gov/system/files/documents/2024-10/final_lcri_fact-sheet_statespws.pdf) defines a galvanized-requiring-replacement service line as galvanized service piping now or formerly downstream of lead service piping, or currently downstream of unknown service material. Interior branches need their own condition record rather than automatic assignment of that service-line inventory label.

Separate accredited laboratory tap-water testing, material identification and deposit analysis. Record stagnation, sample volume, location, filter status and disturbance history under the selected protocol. Clear water and one low lead result do not characterize every outlet or deposit in the building.

Before disturbing suspect scale, establish occupant communications, potable-water arrangements and applicable utility/facility flushing and filtering instructions. [EPA's lead-in-drinking-water guidance](https://www.epa.gov/ground-water-and-drinking-water/basic-information-about-lead-drinking-water) sets a health goal of zero lead; a system action level does not establish a safe individual tap. Assign water-quality release separately from structural acceptance.

How do leak history and consequences set replacement priority?

Count independent confirmed failure episodes by segment. Several work orders for one leak remain one episode; identify the mechanism only when a failed part or investigation supports it. Preserve absolute counts, observation time, exposed length, damage and missing-record periods.

Use consequences and isolation capability alongside recurrence. A small leak over electrical equipment can demand faster action than a larger leak in an accessible, isolated room. The categories below are Anvilfield's action framework; water-quality response can be immediate and concurrent with leakage control.

Table 6. Failure-history severity and action

When is local repair enough?

Choose local repair for a demonstrated local cause, usable tie-ins, adequate flow and an acceptable water-quality plan. Replace a riser or zone when failures, restricted flow or joint damage recur within it. Plan a building repipe when the evidence spans several zones, isolation cannot support essential service, or repeated access and restoration make piecemeal work impractical.

Flushing removes loose material; it does not restore missing steel or weakened threads. Descaling and lining require a separate approved rehabilitation scope addressing substrate condition, potable suitability and release. [New York's 2025 plumbing code §601.5](https://dos.ny.gov/nys-plumbing-code-noa-7182025) references ASTM F2831-19 for nonstructural epoxy rehabilitation of pressure piping; a barrier coating does not replace lost structural wall. Preserve deposit evidence and the water-quality plan before scale removal.

How do you compare failure histories fairly?

Divide confirmed episodes by observed pipe length and time, then express the result per 100 pipe-ft-years. Anvilfield's worked register uses four episodes over 400 ft for three years: 1,200 pipe-ft-years and 0.33 episodes per 100 pipe-ft-years. Formula: rate = episodes × 100 / (observed feet × observed years). Missing records stay missing; do not annualize them as zero failures.

How do you turn survey findings into an occupied-building repipe?

Set replacement boundaries at sound, accessible, approved tie-ins. Include fittings, supports, valves, insulation, abandoned branches, penetrations and finish restoration. A failed sample does not establish the adjoining concealed threaded connection as a usable tie-in. Carry unresolved connections as investigation and enabling quantities.

Public-owner bid documents should identify each service boundary, temporary-water duty, release condition and restoration package so bidders price the same occupied-building work. PorchRocket Bid Control shows an estimator who won past public plumbing contracts and the award amounts for comparison with a phased repipe scope.

Anvilfield's base program stages common mains before four riser-pair phases serving three units each. The selected allowance is one six-hour cutover per pair after preparation, feasible only when the approved testing/release procedure fits or a commissioned alternate supply remains available. Laboratory clearance and required disinfection dwell control actual release.

Table 7. Phased replacement scope and release boundaries

What must temporary water and isolation provide?

Draw temporary and permanent paths separately. Select potable-rated temporary components and required backflow protection under the adopted code, then commission the temporary supply before interrupting the original. Bottled water supplies drinking needs; toilets, handwashing, hot water and essential equipment require their own continuity arrangements.

Prove the [isolation valve](/field-guides/glossary/isolation-valve/) boundary under a controlled outage: isolate all feeds, relieve trapped pressure at a designated drain and verify that flow stops and pressure does not rebuild. Trace hot/cold crossfeeds and return connections if isolation fails; a closed handle alone proves nothing. Price temporary capacity, temperature/stagnation controls, routing, freeze protection, monitoring and removal. Use [isolation valve selection](/field-guides/plumbing/plumbing-valve-types-selection-isolation/) to specify shutoff duty. Disconnect old dead ends from the live system and update the retained-pipe map after each cutover.

Who authorizes the outage and releases each phase?

Name the installing/testing contractor, electrical contractor, facility water-management lead and required inspector or health-authority acceptance. The owner authorizes the outage and occupant arrangements. Record the release signatories, overrun contact and fallback or rollback procedure before starting.

Tell occupants which rooms and fixtures lose hot/cold water, the approved start/end windows, alternate arrangements, access needs and contact route. Include accessibility accommodations and essential uses such as dialysis, sterilization and food preparation where present. Apply the facility's notice requirements. Four riser windows total 24 scheduled window-hours, not 24 labor-hours; mains, preparation and commissioning are additional.

What must happen before cutting and before returning water?

The [2025 Plumbing Code of New York State §601.3](https://dos.ny.gov/nys-plumbing-code-noa-7182025) requires other approved grounding before metallic water service piping used for electrical grounding is replaced with nonmetallic pipe. Identify grounding-electrode and bonding connections before dismantling metal. Interior metal-system bonding remains a separate electrical scope under the locally adopted electrical code.

Have that scope identify retained metal sections, insulating transitions, equipment connections, required jumpers and final verification. A dielectric fitting does not resolve electrical continuity. Specify the applicable electrical work from the actual system rather than assigning a universal jumper size in a plumbing survey.

Which tests and release requirements belong in the scope?

Under New York's 2025 §312.6, prove a completed water-supply section tight with potable-source water at no less than working pressure for at least 15 minutes. Specify water testing for this scope; the code's air alternative excludes plastic. Establish boundaries, stabilization, equipment exclusions, witnesses and the selected product's additional requirements in the [hydrostatic pressure testing](/field-guides/plumbing/hydrostatic-pressure-test-plumbing/) plan; avoid imposing a new-pipe proof test on all retained corroded GI.

New York's 2025 §610.1 requires purging and disinfection before use under applicable state Department of Health regulations. Specify the approved procedure and required sampling through the [potable-water disinfection and flushing](/field-guides/plumbing/potable-water-disinfection-flushing-chlorination/) scope. Pressure tightness alone does not establish water-quality release.

[CDC's January 3, 2025 potable-water guidance](https://www.cdc.gov/control-legionella/php/toolkit/potable-water-systems-module.html) recommends at least weekly flushing of low-flow runs and dead legs. Maintain temperature and detectable disinfectant residual in occupied wings throughout construction; assign monitoring and flushing duties to the facility water-management team.

Repeat pre/post pressure and flow at the same outlets, demand and elevations. Check hot-water return operation where present. Keep hydraulic delivery, leakage acceptance and water-quality clearance as separate release records.

Where do manufacturer instructions change selection?

[Aquatherm's June 2025 Design and Planning Guide, page 3.04](https://aquatherm.com/wp-content/uploads/2025/06/DesignPlanningGuideJune2025.pdf) excludes its products installed in domestic hot-water recirculation after January 1, 2025 from its manufacturer warranty. Review the return-loop duty explicitly; this restriction belongs to that manufacturer, not every PP-R or PP-RCT system. Resolve code, product testing and health-authority release requirements in the approved scope before setting outage windows.

How much does a galvanized pipe condition survey cost and how long does it take?

Anvilfield estimates $7,590 for the defined eight-sample, 24-station survey, using 56 person-hours, $840 in laboratory/consumable allowances and 15% contingency. Varying the selected labor costs by 20% gives $6,265 to $8,915. Access, extra sampling groups, protected work and restoration determine additions.

Anvilfield estimates three working days plus laboratory turnaround: one field day with three survey staff, one sampling day with two plumbers and a UT specialist, and one reporting day. Eight-hour assignments total 48 field person-hours plus eight reporting hours; access and shutdown windows can split those visits.

Table 8. Survey cost worksheet

Estimate method, November 5, 2026: multiply selected person-hours by selected billable rates, add examination/consumable allowances, then apply contingency once to direct cost. These selected inputs are not surveyed market rates. They include reinstatement and baseline UT verification; expanded pit mapping, travel, night work, hazardous-material controls, temporary supply and major finish restoration require separate quantities.

How should the later repipe be priced?

Measure lengths and fittings by diameter, service and access class through [plumbing estimating and takeoff](/field-guides/plumbing/plumbing-estimating-takeoff/). The 600 ft main/riser allowance excludes unmeasured branches and any return loop. Add supports, valves, insulation, temporary water, electrical work, tests/disinfection, access panels and [pipe penetrations and firestop](/field-guides/plumbing/pipe-penetration-firestop-sleeves/).

Keep unknown tie-ins, finish classes and additional sampling visible as allowances or unit-price items tied to release conditions. Separate survey, enabling work and construction quantities. Product choice follows the documented hot/cold/return duty and approved material submittal.

Field checklist and owner turnover

Copy this checklist to each segment sheet. Record segment ID, evidence file, status, action owner and due date beside each item. Use complete, open or not applicable; an unverified segment remains open until its investigation or replacement action is assigned.

• Define potable-water systems, zones and essential uses; obtain utility lead-service history.
• Record code editions, product requirements, hazardous-material controls and approved openings/outages.
• Trace and label segments and valves; prove isolation.
• Locate grounding/bonding connections and complete required electrical preparation.
• Agree occupant notices, alternate drinking water, sanitation and hot-water arrangements.
• Check instruments; record point elevations, static/flowing psi, gpm and background demand.
• Bracket devices and fixtures before assigning corroded-pipe loss.
• Label and photograph cutouts before cleaning; preserve bore, orientation and joint evidence.
• Log UT setup, calibration, ring/clock positions, minima and unresolved no-reads.
• Apply laboratory protocols and preserve chain of custody where used.
• Separate restriction, wall, joint and retained-lead findings.
• Deduplicate leaks; record observed length/time, gaps and consequences.
• Map replacement tie-ins and every retained or inaccessible GI segment.
• Quantify temporary water, electrical work, supports, firestop, insulation and finishes.
• Set phase windows, overrun response, water-management duties and release signatories.
• Document tests, disinfection, required sampling and restored essential fixtures.
• Repeat matched-demand measurements and check return operation.
• Deliver as-builts, concealed-work images, samples/tests, approvals, warranties and review dates.

At turnover, list remaining galvanized segments by ID with the reason for retention, access limitations and next review date. Replace planned quantities with installed quantities and approved changes. Include permit closeout where applicable.

Sources checked and how to cite this page

Byline: Anvilfield. Reviewed November 5, 2026. Primary sources were reopened on that date; ASTM public scopes support method descriptions. New York provisions are jurisdictional examples: the project's adopted code and amendments control elsewhere.

• [DCWASA/HDR, retained-lead investigation, September 2009](https://archive.epa.gov/dclead/web/pdf/galvanized%20project%20report.pdf)
• [ASTM A53/A53M-24, public material scope](https://store.astm.org/a0053_a0053m-24.html)
• [EPA, service-line inventory guidance, August 2022](https://www.epa.gov/system/files/documents/2022-08/Inventory%20Guidance_August%202022_508%20compliant.pdf)
• [ASTM E797/E797M-21, public UT scope](https://store.astm.org/e0797_e0797m-21.html)
• [Evident, dual-element corrosion gauging, undated](https://ims.evidentscientific.com/en/applications/corrosion-gaging-dual-element-transducers)
• [Evident, coating measurement tutorial, undated](https://ims.evidentscientific.com/en/learn/ndt-tutorials/thickness-gauge/coatings)
• [EPA, LCRI technical fact sheet, October 2024](https://www.epa.gov/system/files/documents/2024-10/final_lcri_fact-sheet_statespws.pdf)
• [EPA, EPANET 2.2 User Manual, 2020](https://raw.githubusercontent.com/USEPA/EPANET2.2/master/User_Manual/EPANET_User%27s_Manual_2.2.0.pdf)
• [New York State/ICC, 2025 Plumbing Code, July 2025](https://dos.ny.gov/nys-plumbing-code-noa-7182025)
• [Wheatland Tube, Standard Pipe dimension brochure](https://www.wheatland.com/wp-content/uploads/2017/12/Standard-Pipe-Brochure-2.pdf)
• [CDC, potable-water Legionella controls, January 3, 2025](https://www.cdc.gov/control-legionella/php/toolkit/potable-water-systems-module.html)
• [Aquatherm, Design and Planning Guide, June 2025](https://aquatherm.com/wp-content/uploads/2025/06/DesignPlanningGuideJune2025.pdf)
• [Hydraulic Institute, formula reference, Version 1](https://www.pumps.org/wp-content/uploads/2025/02/PSC-Exam-Formula-Reference-Sheet.pdf)
• [EPA, Basic Information about Lead in Drinking Water](https://www.epa.gov/ground-water-and-drinking-water/basic-information-about-lead-drinking-water)
• [OSHA, 29 CFR 1926.1101, asbestos in construction](https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1101)
• [OSHA, 29 CFR 1926.62, lead in construction](https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.62)

Update log: 2026-11-05: Final article review: verified source claims and calculations; clarified sampling attribution, fixture criteria, nonstructural lining, isolation, access controls and staffing.

How to cite this page: Anvilfield, Galvanized pipe corrosion survey field guide for a building repipe, 2026, https://anvilfield.com/field-guides/plumbing/galvanized-pipe-corrosion-condition-survey/

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