Polybutylene Pipe: Where It Was Installed and How Much Housing Dates From the PB Years

Polybutylene pipe years: Nevada and Florida permitted the most homes relative to today's stock

Building permits were issued for 21,352,930 US housing units in 1980 to 1995, equal to 14.4 percent of the 148,228,967 housing units the ACS counted in 2025. Nevada (22.8 percent) and Florida (22.4 percent) lead; the District of Columbia (2.6 percent) and West Virginia (4.2 percent) trail.

Nevada issued permits for 316,438 units in 1980 to 1995 against a 2025 stock of 1,385,027 units, which puts it first on the ratio even though it ranks only 24th by raw count. Florida issued permits for 2,420,864 units against 10,788,709, a ratio of 22.4 percent, and is the only state in the top two on both measures (Census BPS, ACS 2025 B25001).

Texas is the counterweight. Texas issued permits for 1,756,830 units in the PB years, third in the country, but Texas kept building after 1995, so PB-era permits equal only 13.7 percent of its 2025 stock, below the national 14.4 percent. In all, 19 jurisdictions sit at or above the national ratio.

PB-era permits: Privately owned housing units authorized by building permits in 1980 to 1995 in the Census Building Permits Survey state annual files (estimates with imputation, all structure types). The Cox settlement class covered PB installed from January 1, 1978 to July 31, 1995; the state annual series starts in 1980.

California, Florida and Texas issued a third of all PB-era permits

California (12.6 percent), Florida (11.3 percent) and Texas (8.2 percent) together account for 6,868,906 of the 21,352,930 PB-era permits, or 32.2 percent. The Census South region accounts for 43.3 percent, and the ten largest states for 55.8 percent.

A 2000 memo by the law firm Cozen O'Connor stated that most PB systems were believed to be installed in Florida, California and Texas, the three states with most of the litigation (Cozen O'Connor, 2000). Permits put 32.2 percent of PB-era construction in those three states. If the memo's claim is right, PB use per permitted unit in those states was well above the rate elsewhere, or the claim reflects where lawsuits were filed rather than where pipe was installed. The opened sources do not settle which.

The same memo said PB suits had been filed in 36 states by 2000. California alone issued permits for 2,691,212 units in 1980 to 1995, the largest count, but its 2025 ratio of 17.9 percent ranks ninth because its stock is the country's largest.

Two in three PB-era permits were issued in the 1980s, the acetal-fitting years

Permits for 14,295,188 units, 66.9 percent of the PB-era total, were issued in 1980 to 1989. The 1983 to 1986 boom alone accounts for 6,789,752 units, with a peak of 1,769,443 in 1986 and a low of 948,794 in 1991.

Timing matters because the fittings changed. A Pillar To Post information sheet says copper inserts and crimp rings were introduced in about 1986 after joints with plastic (acetal) inserts and aluminum crimp rings began to leak, and that the plastic fittings were not fully off the market until about 1993 (Pillar To Post). Most PB-era permits therefore predate the metal-fitting switch.

Single-family units were 14,139,460 of the PB-era permits, or 66.2 percent. The rest were apartments and other multi-unit buildings; the Cox class covered houses, condominiums, townhouses, commercial properties and mobile homes alike (Cox notice, archived).

Manufactured homes, the PB market that permit counts miss

Manufacturers shipped 3,938.3 thousand new manufactured homes in 1980 to 1995, and Census excludes HUD-code manufactured homes from permit statistics. A 1983 industry document put PB in well over 80 percent of new mobile homes and RVs. The ACS counts 129.7 surviving 1980 to 1999 homes for every 100 units permitted in those years.

Industry material filed with an Alaska Senate committee in 1983 says PB was first used in mobile homes in 1972 and had become the main hot and cold water pipe in that industry, used in well over 80 percent of the mobile homes and recreational vehicles then produced (Alaska Legislature, SB 214 file). That is the manufacturer side's own statement. The Cox settlement gave mobile homes a shorter window: a qualifying leak within 10 years of installation and a claim within 11 years.

The cross-check shows where permits understate PB-era building. Across the United States, the ACS 2025 counts 35,663,034 homes built in 1980 to 1999 against 27,495,475 units permitted in those years. Adding 5,376.6 thousand manufactured home shipments brings the supply to 32,872,075, or 92.2 percent of the surviving count; the remaining 2,790,959 homes reflect unpermitted rural areas, misreported year built and survey error, net of demolitions.

Six jurisdictions show at least 200 surviving homes per 100 permits: West Virginia (404.6), Montana (282.9), the District of Columbia (241.8), Arkansas (234.3), Mississippi (226.5) and Alabama (212.0). In those states the permit ratio on the map understates PB-era housing. The District of Columbia has almost no manufactured housing, so its ratio more likely reflects year-built reporting than missing permits; treat it as noise.

From HUD's 1978 materials bulletins to the 2009 claim cutoff

HUD Use of Materials Bulletins for PB water distribution are dated April 25, 1978. The Cox class window ran from January 1, 1978 to July 31, 1995, and the last date to file a new Cox claim was May 1, 2009.

Two federal records frame the start and the present. HUD's Minimum Property Standards still list Use of Materials Bulletin 76 (CPVC and PB hot and cold water distribution) and Bulletin 78 (PB cold water service), both dated April 25, 1978 (24 CFR Part 200, Appendix A). The HUD manufactured home standard still lists ASTM D3309, the PB hot and cold water specification, among accepted plastic piping standards (24 CFR 3280.604). A listing is not evidence that PB is still sold or installed.

What Cox v. Shell paid for, and how the Spencer settlement differed

Shell Oil and Hoechst Celanese committed $950 million to the Cox fund, approved on November 17, 1995, plus $45 million in class counsel fees. DuPont's separate Spencer settlement was $120 million and paid 10 percent of replumb and leak-damage costs.

The Cox fund grew from a tentatively approved $850 million in August 1995 (Tampa Bay Times, 1995) to $950 million in the court notice, a rise of 11.8 percent. An earlier $750 million three-company settlement from October 1994 had been rejected by a Texas judge in February 1995. The defendants denied, and the 1999 notice says they still denied, any legal liability relating to PB plumbing.

Cox relief depended on a qualifying leak. Single-family homes with metal insert fittings had 16 years from installation for a qualifying leak (not later than January 31, 2009) and 17 years to file (not later than May 1, 2009); other structures had 13 and 14 years. Once 80 percent of the fund was spent, replumbs took priority over cash payments (Cox notice). The Spencer settlement, filed in Greene County, Alabama, paid 10 percent of replumb cost and 10 percent of leak damage if the replumb was done within 15 years of installation (Contractor, 2003).

Six million, nine million or "several million": the published counts do not agree

Published counts of PB homes run from "several million" (the settlement administrator, 2000) to 6 million homes plus 3 million mobile homes (Cozen O'Connor, 2000). None of the opened sources gives a method. Set against Census volumes, 6 million site-built homes would equal 28.1 percent of PB-era permits, and 3 million mobile homes 76.2 percent of PB-era shipments.

The Tampa Bay Times reported in 1995 that the pipe had been used in about 6 million homes since 1978, half of them mobile. The Cozen O'Connor memo counts 6 million homes plus an additional 3 million mobile homes. The two agree on about 3 million mobile homes but differ on site-built homes: about 3 million in one, 6 million in the other, which would equal 14.0 or 28.1 percent of PB-era permits. The 1983 industry figure of well over 80 percent of new mobile homes fits the 3 million mobile estimate, which would equal 76.2 percent of the 3,938.3 thousand manufactured homes shipped in 1980 to 1995. Pillar To Post's "perhaps up to 50 percent" of mobile homes points lower.

Taken together, 9 million PB homes would equal 35.6 percent of the 25,291,230 units permitted or shipped in 1980 to 1995. The often repeated range of 6 to 10 million homes could not be traced to an original count in any source opened for this report; see the excluded list in the methodology.

Chlorine, crimp rings and acetal fittings: the three failure theories

No source opened for this report presents a controlled test, so the causes below are the theories recorded in litigation-era documents. They point to chlorine attacking the acetal fittings and the pipe, stress from crimping, and oxidation of the pipe itself.

The Cozen O'Connor memo lists three theories: acetal fitting resins and polybutylene deteriorate on exposure to chlorine in public water; high crimp force put excess stress on pipe and fittings; and the pipe broke down early through oxidation. In 1995 a Hoechst representative told reporters the pipes leaked because they could not resist chemicals added to water in many parts of the country (Tampa Bay Times).

Red River Mutual, a property insurer, lists chlorine and other water chemicals, pipe age and faulty installation as contributing factors and notes that failures start inside the pipe, so condition cannot be judged by looking (Red River Mutual). The 1983 industry material had projected a normal life of at least 50 years. For how long the replacement materials last, see how long copper pipes last.

Florida's insurer of last resort stopped writing older PB homes in 2022

Citizens Property Insurance Corporation rule 206.B, for new business from February 1, 2022, makes risks over 20 years old with polybutylene piping uninsurable by Citizens. In 2026 the youngest home in the Cox installation window is 31 years old.

Citizens' April 2022 agent bulletin states that new-business risks over 20 years old with polybutylene piping are not insurable by Citizens under rule 206.B for its HO-3 and HO-8 forms (Citizens, 2022). Because the Cox window closed on July 31, 1995, every home plumbed with PB in that window passed the 20-year mark by 2015.

In 2023 Citizens told NBC 6 South Florida that, like most of the insurance industry, it does not insure properties with polybutylene piping, and Florida's Office of Insurance Regulation said an insurer may consider the age of a home's plumbing when offering coverage (NBC 6, 2023). Florida issued permits for 2,420,864 units in the PB years, the second highest count, which is why the rule touches a large share of older Florida housing. This report is not legal, insurance or real estate advice. State figures are permits issued or homes built during the PB years, never counts of homes with polybutylene.

What a PB-era permit count can tell a kitchen or bath remodeler

A home built or replumbed in 1978 to 1995 is a candidate for PB; a permit ratio only says how common such homes are in a state. The Cox notice describes what to look for: flexible gray, silver or black supply pipe indoors and blue, gray or black yard service lines.

The Cox notice defines PB plumbing as a potable water supply system of flexible PB pipe joined by acetal (hard gray or white plastic) or copper or brass insert fittings, clamped with aluminum or copper crimp rings. PB was not used for drain, waste or vent pipe (Cox notice). Pillar To Post notes that rigid plastic pipe with glued joints is PVC or CPVC, and that PEX, often red or blue, is a different material that can be mistaken for PB.

Supply lines are easiest to inspect when walls are open, which is why repiping questions often surface during a bathroom or kitchen project. For budgeting context see the bathroom remodel cost guide and the kitchen remodel timeline, and for vetting a plumber or remodeler see how to choose a remodeling contractor. Related KBR research: water damage statistics, how old is my house and the lead pipes map.

State-by-state findings

1. Building permits were issued for 21,352,930 US housing units in 1980 to 1995 (Census BPS state annual files).^[1]
2. PB-era permits equal 14.4 percent of the 148,228,967 US housing units in the ACS 2025 1-year estimates.^[1][5]
3. Nevada's 316,438 PB-era permits equal 22.8 percent of its 1,385,027 housing units in 2025, the highest state share.^[1][5]
4. Florida's 2,420,864 PB-era permits equal 22.4 percent of its 10,788,709 housing units in 2025.^[1][5]
5. California (2,691,212), Florida and Texas (1,756,830) together issued 32.2 percent of US permits in 1980 to 1995.^[1]
6. Permits for 14,295,188 units, 66.9 percent of the 1980 to 1995 total, were issued in the 1980s; the annual peak was 1,769,443 in 1986.^[1]
7. Manufacturers shipped 3,938.3 thousand new manufactured homes in the United States in 1980 to 1995 (Census MHS).^[8]
8. Nationally, the ACS 2025 counts 129.7 surviving homes built in 1980 to 1999 per 100 units permitted in those years; West Virginia shows 404.6.^[1][6]
9. HUD Use of Materials Bulletins 76 and 78 for PB water piping are dated April 25, 1978 (24 CFR Part 200, Appendix A).^[13]
10. The Cox v. Shell Oil settlement fund was $950 million, with $45 million in class counsel fees paid on top (Obion County Chancery Court notice, 1999).^[9]
11. DuPont's Spencer settlement of $120 million paid 10 percent of replumb and leak-damage costs.^[17][19]
12. The filing deadline for all new Cox claims expired on May 1, 2009 (archived CPRC page).^[11]
13. Citizens Property Insurance (Florida) rule 206.B, effective February 1, 2022, makes new-business risks over 20 years old with PB piping uninsurable by Citizens.^[15]
14. Industry material filed in Alaska in 1983 said PB was used in well over 80 percent of new mobile homes and RVs.^[16]

Rankings and ratios we derived

Download the calculations (CSV)

Executive summary

• Permits were issued for 21,352,930 US housing units in 1980 to 1995, equal to 14.4 percent of the 148,228,967 units in the 2025 ACS.
• Nevada (22.8 percent), Florida (22.4 percent), Virginia (20.9 percent), Arizona (20.8 percent) and Hawaii (20.6 percent) have the highest PB-era shares.
• California, Florida and Texas issued 32.2 percent of PB-era permits; Texas built so much afterwards that its share of today's stock is 13.7 percent.
• Manufactured homes, which permit counts omit, added 3,938.3 thousand shipments in 1980 to 1995, and a 1983 industry document put PB in well over 80 percent of new mobile homes and RVs.
• The Cox v. Shell settlement committed $950 million for PB installed from January 1, 1978 to July 31, 1995; new claims closed on May 1, 2009.
• Published counts of PB homes range from "several million" to 6 million homes plus 3 million mobile homes, with no stated method.
• Since February 1, 2022, Florida's Citizens Property Insurance will not write new policies on homes over 20 years old with PB piping.

Frequently asked questions

Related guides, services and research

• Small bathroom remodel cost
• How to choose a contractor
• GFCI Requirements: Where Kitchens and Bathrooms Need Protection, Code by Code
• Hard Water Map: Tap Water Hardness in the 50 Largest US Cities (2026)
• Heat Pump Water Heater: Operating Cost and Payback in Every State
• Home Improvement Contractor License Requirements by State (2026)
• All kitchen and bath research

Reproduce this analysis

Every figure comes from the files below. The scripts that pulled and computed them are kept with the report and can be re-run.

Data quality and exclusions

• Used the 'estimates with imputation' columns of the BPS files, not the 'reported only' columns; for 1980 the reported-only US single-family count is 692,834 against 710,390 with imputation.
• Dropped 13 region and division rows per BPS file (4 regions, 9 divisions) and kept 51 state and DC rows plus the US row; the 51 state totals sum exactly to the US total of 21,352,930 for 1980 to 1995.
• Excluded Puerto Rico and the Virgin Islands, which appear in recent BPS files but not in the 1980 to 1999 series, and Puerto Rico's ACS row.
• Kept only GEO_ID rows for the US, 50 states and DC from the ACS .dat files (52 rows each) and discarded all other summary levels.
• Summed 12 monthly manufactured home shipment values per year (in thousands, as published, one decimal) instead of using seasonally adjusted annual rates.
• Read the Cox notice, FAQ and settlement status from Internet Archive captures because the live pbpipe.com domain now shows a registrar parking page; each capture is labelled with its date.
• Did not use FindLaw, InterNACHI, ASTM or the Solvay PDF because they refused automated access (HTTP Forbidden); facts that depended on them were dropped.

Methodology

Source selection: Census Building Permits Survey state annual files (st1980a.txt to st1999a.txt) for construction during the PB years, ACS 2025 1-year tables B25001 and B25034 from the table-based summary file (the newest release, published October 29, 2026; the ACS API returned no data without a key), and the Census Manufactured Housing Survey shipments history. Settlement terms come from the Cox court notice and administrator pages, read through labelled Internet Archive captures because pbpipe.com is now a parked domain. Federal acceptance comes from the eCFR. Press reports and a law firm memo are used only for dated events and for published estimates, which are shown side by side.

Inclusion and exclusion: the PB window is 1980 to 1995 because the state annual permit series starts in 1980 and the Cox class window ends July 31, 1995; 1978 and 1979 permits and the August to December 1995 permits that fall outside the class window are noted as limits rather than estimated. Units are the 'estimates with imputation' columns for all structure types. Puerto Rico and territories are excluded. Claims that could not be traced to an opened source, including the widely repeated 6 to 10 million range, a 320,000 replumbed homes figure and the PB2110 pipe marking, are listed in excluded.md.

Conflicting numbers: the Cox fund appears as $850 million (tentative, August 1995) and $950 million (court notice); the report uses the court notice and shows the change. Mobile home shares of 50 percent, half, and well over 80 percent are shown with their sources rather than reconciled.

Derived metrics: PB-era share of stock = units authorized 1980 to 1995 / ACS 2025 housing units; survivors per 100 permits = ACS homes built 1980 to 1999 / units authorized 1980 to 1999; concentration and implied-rate metrics as listed in derived_metrics.csv. All are reproducible with scripts/build_data.py and scripts/compose_data.py from the files in raw/.

Limitations: permits are authorizations, not completions, and do not record plumbing material; the permit universe grew from about 16,000 places (1978 to 1983) to about 17,000 (1984 to 1993) and about 19,000 (1994 onward), so early-year counts cover fewer places; manufactured homes and unpermitted areas are missing; ACS figures carry sampling error.

Last updated 2026-11-01. The atlas will be refreshed when the ACS 2026 1-year estimates are released.

This report presents published data with its limitations. It is not legal, financial or investment advice.

Sources, ranked by quality

Tier 1: primary and official sources (16)

• [1] U.S. Census Bureau. Building Permits Survey, state annual files st1980a.txt to st1999a.txt (estimates with imputation). 1980 to 1999, annual. Accessed 2026-11-01.
• [2] U.S. Census Bureau. Building Permits Survey: Methodology (universe of permit-issuing places, imputation). Universe history 1959 to 2023. Accessed 2026-11-01.
• [3] U.S. Census Bureau. Residential Building Permits Survey Documentation: State ASCII Files (February 9, 2022). File layout. Accessed 2026-11-01.
• [4] U.S. Census Bureau. Building Permits Survey: Definitions (housing unit, new residential construction coverage). Current definitions. Accessed 2026-11-01.
• [5] U.S. Census Bureau. American Community Survey 2025 1-year, Table B25001 Housing Units (table-based summary file). 2025 (released October 29, 2026). Accessed 2026-11-01.
• [6] U.S. Census Bureau. American Community Survey 2025 1-year, Table B25034 Year Structure Built (table-based summary file). 2025 (released October 29, 2026). Accessed 2026-11-01.
• [7] U.S. Census Bureau. 2025 ACS Data Release Schedule (updated October 29, 2026). 2025 ACS releases. Accessed 2026-11-01.
• [8] U.S. Census Bureau. Manufactured Housing Survey: Shipments of New Manufactured Homes, 1959 to 2020 (shiphist.xlsx). 1980 to 1999 used, monthly not seasonally adjusted. Accessed 2026-11-01.
• [9] Consumer Plumbing Recovery Center (court-established administrator), pbpipe.com. Notice of Class Action and Settlement, Cox v. Shell Oil Co., Civil Action 18,844, Chancery Court for Obion County, Tennessee (dated August 26, 1999), Internet Archive capture of the official page (labelled archive copy). Settlement approved November 17, 1995; notice August 26, 1999. Accessed 2026-11-01.
• [10] Consumer Plumbing Recovery Center, pbpipe.com. CPRC Frequently Asked Questions, Internet Archive capture of the official page (labelled archive copy). Captured October 3, 2000. Accessed 2026-11-01.
• [11] Consumer Plumbing Recovery Center, pbpipe.com. The Polybutylene Pipe Settlement Fund home page (filing deadline notice), Internet Archive capture of the official page (labelled archive copy). Captured August 4, 2009. Accessed 2026-11-01.
• [12] Consumer Plumbing Recovery Center, pbpipe.com. The Polybutylene Pipe Settlement Fund home page (settlement closed), Internet Archive capture of the official page (labelled archive copy). Captured May 29, 2011. Accessed 2026-11-01.
• [13] U.S. Department of Housing and Urban Development via eCFR. 24 CFR Part 200, Appendix A: Standards Incorporated by Reference in the Minimum Property Standards (Use of Materials Bulletins 76 and 78). eCFR current as of October 29, 2026. Accessed 2026-11-01.
• [14] U.S. Department of Housing and Urban Development via eCFR. 24 CFR 3280.604 Materials (Manufactured Home Construction and Safety Standards, plumbing). eCFR current as of October 29, 2026. Accessed 2026-11-01.
• [15] Citizens Property Insurance Corporation (Florida). Clarification of February 1, 2022, Eligibility Rules (agent bulletin, April 28, 2022). Rules effective February 1, 2022. Accessed 2026-11-01.
• [16] Alaska State Legislature, Senate Labor and Commerce Committee. Senate Bill 214 committee file, 'An act relating to the plumbing code' (includes polybutylene industry materials filed with the committee). 1983. Accessed 2026-11-01.

Tier 2: trade bodies, market research, company data (1)

• [23] Red River Mutual. Safety guide: Plumbing, Polybutylene. Page copyright 2026. Accessed 2026-11-01.

Tier 3: journalism and expert commentary (6)

• [17] Tampa Bay Times. Plumbing suit deal okayed, may not last (archive, August 2, 1995). 1995. Accessed 2026-11-01.
• [18] The Seattle Times. Someone Besides You May Be Responsible For Those Leaky Pipes (October 31, 1998). 1998. Accessed 2026-11-01.
• [19] Contractor Magazine. Polybute Settlement Money Still Available (October 1, 2003). 2003. Accessed 2026-11-01.
• [20] NBC 6 South Florida. Does Your Home Have Poly Pipes? Getting Insurance May Be Difficult (March 13, 2023). 2023. Accessed 2026-11-01.
• [21] Cozen O'Connor. Polybutylene Pipes and Plumbing Systems (William G. Flint, 2000). 2000. Accessed 2026-11-01.
• [22] Pillar To Post. Polybutylene Pipe (Information Series V1.0). Undated, uploaded January 2019. Accessed 2026-11-01.