States → Pennsylvania
State profile · EPA SDWIS + UCMR5
Pennsylvania Drinking Water Quality
7,701 public water systems serve 12,630,061 people across Pennsylvania, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.
- 7,701
- Water systems
- 1,159,868
- Total violations
- 97.1%
- Systems w/ a violation
- 57.6%
- PFAS detection rate
The verdict
Across Pennsylvania, 7,480 of 7,701 water systems (97.1%) carry at least one EPA violation, and 224 of 389 UCMR5-tested systems show PFAS.
- 1,159,868
- Total EPA violations on record
- 6%
- Health-based (MCL / treatment)
- 97.1%
- Systems with ≥1 violation
- 57.6%
- UCMR5 PFAS detection rate
Water Systems
7,701
Total Violations
1,159,868
Violation Rate
97.1%
PFAS Detection
57.6%
224 of 389 tested
Violation Composition
How Pennsylvania's 1,159,868 violations break down by type, per EPA SDWIS classification.
Health-based (68,517) Monitoring/Reporting (1,091,351)
| Metric | Value | Share |
|---|---|---|
| Public water systems | 7,701 | - |
| Population served | 12,630,061 | - |
| Total violations | 1,159,868 | 100% |
| Health-based violations | 68,517 | 5.9% |
| Systems with violations | 7,480 | 97.1% |
| PFAS detection rate | 224 of 389 | 57.6% |
Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.
Largest Water Systems
Philadelphia Water Department
Philadelphia, PA · 1,600,000 served
Aqua PA Main System
Bryn Mawr, PA · 822,600 served
PA Amer Water Co-Pittsburgh
McMurray, PA · 686,000 served
Pittsburgh Water & Sewer Auth
Pittsburgh, PA · 520,000 served
Erie City Water Authority
Erie, PA · 220,001 served
York Water Co
York, PA · 206,762 served
West View Water Authority
Pittsburgh, PA · 200,000 served
Mawc Sweeney Plant
Greensburg, PA · 143,000 served
Chester Water Authority
Chester, PA · 140,437 served
PA Amer Water Co Lake Scranton
Wilkes Barre, PA · 134,570 served
Mawc Yough Plant
Greensburg, PA · 133,000 served
Wilkinsburg-Penn Jt Water Auth
Wilkinsburg, PA · 125,000 served
City of Lancaster
Lancaster, PA · 120,000 served
Lca Allentown Division
Allentown, PA · 118,000 served
City of Bethlehem
Bethlehem, PA · 117,259 served
Veolia Water
Harrisburg, PA · 110,000 served
PA American Water Co West
Mechanicsburg, PA · 105,127 served
Easton Area Water System
Easton, PA · 96,867 served
Reading Area Water Authority
Reading, PA · 95,100 served
North Penn Water Authority
Lansdale, PA · 91,941 served
Most Violations
#1 Congregation Ohr Menachem Canadensis
9,908 #2 Salem Heights Estate Lake Ariel
6,572 #3 PA American Audubon Norristown
5,456 #4 Aqua PA Sun Valley Whitehaven
4,752 #5 Cobbs Lake Preserve Lake Ariel
3,507 #6 Robinwood Village Saylorsburg
3,499 #7 Paradise Stream Resor Mount Pocono
3,309 #8 Mount Eagle Water Assoc Howard
3,283 #9 Nottingham Manor M H Court Nottingham
3,266 #10 Tower Springs LLC Malvern,
3,062 #11 Neshaminy Manor Center Warrington
3,037 #12 Sunrise Lakes Sec 12 Moscow
2,993 #13 Newport Boro Water Auth Newport
2,935 #14 Ambler Boro Water Dept Ambler
2,896 #15 McConnellsburg Boro Muni Auth Mc Connellsburg
2,725 Counties in Pennsylvania
Allegheny
69 systems · 2,014,752 served
· 5,241 violations
Philadelphia
6 systems · 1,601,175 served
· 447 violations
Montgomery
172 systems · 1,274,688 served
· 36,032 violations
Bucks
299 systems · 599,107 served
· 59,577 violations
Lancaster
434 systems · 406,457 served
· 39,193 violations
York
208 systems · 389,602 served
· 25,528 violations
Berks
493 systems · 382,268 served
· 54,767 violations
Northampton
205 systems · 334,919 served
· 15,627 violations
Luzerne
251 systems · 325,882 served
· 44,749 violations
Erie
146 systems · 304,235 served
· 23,068 violations
Chester
276 systems · 302,878 served
· 47,248 violations
Lehigh
201 systems · 294,981 served
· 15,405 violations
Dauphin
145 systems · 294,232 served
· 21,033 violations
Westmoreland
82 systems · 262,918 served
· 12,979 violations
Fayette
41 systems · 255,694 served
· 10,137 violations
Cumberland
99 systems · 249,438 served
· 10,230 violations
Monroe
443 systems · 188,975 served
· 72,365 violations
Centre
78 systems · 182,614 served
· 21,783 violations
Beaver
96 systems · 179,116 served
· 14,356 violations
Lackawanna
119 systems · 172,971 served
· 22,460 violations
Butler
182 systems · 159,830 served
· 24,329 violations
Delaware
23 systems · 151,505 served
· 3,592 violations
Cambria
70 systems · 141,807 served
· 19,662 violations
Franklin
122 systems · 136,296 served
· 18,681 violations
Schuylkill
188 systems · 132,673 served
· 19,535 violations
Blair
53 systems · 101,979 served
· 8,263 violations
Lebanon
109 systems · 101,380 served
· 8,644 violations
Mercer
146 systems · 98,473 served
· 18,095 violations
Northumberland
66 systems · 93,484 served
· 9,157 violations
Lycoming
135 systems · 89,254 served
· 31,610 violations
Showing top 30 of 68 counties.
Drinking Water Guides
Frequently Asked Questions
How many water systems are in Pennsylvania? ▼
Pennsylvania has 7,701 public water systems serving approximately 12,630,061 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Pennsylvania? ▼
Pennsylvania has 1,159,868 total drinking water violations on record, with 68,517 classified as health-based violations. 97.1% of water systems in the state have at least one violation.
Has PFAS been found in Pennsylvania drinking water? ▼
Of 389 water systems tested for PFAS in Pennsylvania, 224 had PFAS detected, a 57.6% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Pennsylvania water systems? ▼
Pennsylvania's violation rate is 97.1%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Pennsylvania water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources & Methodology
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.