Allegheny County, Pennsylvania: drinking water report. Allegheny County – Pittsburgh and over 100 surrounding municipalities – sits at the confluence of…
Allegheny County – Pittsburgh and over 100 surrounding municipalities – sits at the confluence of three rivers: the Allegheny, Monongahela, and Ohio. About 1.2 million residents receive water from multiple providers, with the Pittsburgh Water and Sewer Authority (PWSA) serving the city and several authorities handling suburban areas. The rivers carry industrial heritage – steel mills, coal operations, and chemical plants operated along these waterways for over a century.
Pittsburgh has faced national attention for lead in drinking water. A 2016 testing crisis revealed elevated lead levels across the city, linked to aging infrastructure and a treatment chemical change that destabilized lead pipes. PWSA has since invested in corrosion control and lead service line replacement, but the American Water Works Association estimated in 2023 that approximately 27,000 lead service lines remained in the PWSA system.
UCMR5 data shows PFAS detections in county water systems. The three-river watershed receives industrial and municipal discharges from communities upstream. Pennsylvania's proposed PFAS MCLs of 14 ppt for PFOA and 18 ppt for PFOS would be among the stricter state standards nationally. According to the PA DEP's 2024 monitoring data, four water systems in Allegheny County reported PFAS above proposed limits.
Lead is the highest-priority concern for Pittsburgh residents, particularly in homes built before 1950 with original plumbing.
Check your water to see data for your specific area. A dual-purpose filter certified for both lead and PFAS provides the most value. Our water filter guide covers effective options. Pull your detailed report for trend data, and visit our Pennsylvania page for statewide context.
Drinking water is one exposure route. These federal datasets also cover Allegheny County, PA.
The EPA places Allegheny County, PA in Zone 1 - the EPA's highest-risk category, where the predicted average indoor radon level is above 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
78% of homes in Allegheny County, PA were built before 1980, and 37% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Allegheny County, PA averages 9.1 µg/m³, above the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide
Across 39 public water systems serving Allegheny County, PA with EPA lead testing on record, 2 (5.1%) reported a 90th-percentile lead result above the EPA's 15 ppb action level, and the median is 3.7 ppb. 22 water systems serving Allegheny County, PA carry a health-based EPA Safe Drinking Water Act violation.
| Most-cited violation type | Systems affected |
|---|---|
| Total Trihalomethanes (TTHM) | 10 |
| Revised Total Coliform Rule | 3 |
| Total Organic Carbon | 2 |
| Stage 1 Disinfectants and Disinfection Byproducts Rule | 2 |
| Haloacetic Acids (HAA5) | 2 |
Source: EPA Lead and Copper Rule 90th-percentile tap sampling and EPA SDWIS Safe Drinking Water Act enforcement records, aggregated from the public water systems serving this county. Figures are counts of water systems, not a test of any individual home or tap.