Updated April 2026 · EPA SDWIS data
Pennsylvania Drinking Water Quality
5 water systems · 2,789,548 people served · Avg score: 86
Pennsylvania has 5 public water systems serving 2,789,548 people, with an average Water Safety Score of 86 of 100 (good). EPA SDWIS records show 2 systems with at least one open or recent violation.
Pennsylvania Water Systems
Aqua Pa Main System
Bryn Mawr, Pennsylvania
Philadelphia Water Department
Philadelphia, Pennsylvania
Chester Water Authority
Chester, Pennsylvania
Pa Amer Water Co Lake Scranton
Wilkes Barre, Pennsylvania
North Penn Water Authority
Lansdale, Pennsylvania
How Pennsylvania Compares Nationally
Pennsylvania runs 5.0 points above the U.S. average Water Safety Score of 81.0 — meaningfully better than the typical state, usually because of newer infrastructure or stronger state-level enforcement under EPA primacy.
2 of 5 Pennsylvania water systems (40%) have an open or recent EPA violation — well above the U.S. average. The concentration is typical of states with many small rural systems where compliance staffing is thin.
The most-detected contaminants flagged in EPA SDWIS for Pennsylvania are Chlorine (1 systems) and Gross Alpha (1 systems). These typically reflect either source-water characteristics — agricultural runoff for nitrate, geology for arsenic, industrial proximity for PFAS — or distribution-system effects like lead from service lines and disinfection byproducts.
Why Pennsylvania Looks the Way It Does
Three factors usually explain a state's drinking water profile. First, source water — states drawing primarily from deep protected aquifers face fewer treatment challenges than states reliant on surface water downstream of agriculture or industry. Second, infrastructure age — older Northeast and Midwest distribution networks carry more lead service lines and aging treatment plants, which surface as monitoring or contaminant violations. Third, system-size mix — states with many small rural systems concentrate violations because small systems have thinner compliance staffs.
Pennsylvania's federal regulatory enforcement runs under the EPA primacy framework, which delegates Safe Drinking Water Act enforcement to the state drinking water program with EPA oversight. State enforcement capacity varies, which is one of the reasons two neighboring states with similar source water can have very different violation rates in EPA SDWIS records.
How These Numbers Are Calculated
All counts and scores on this page come directly from the EPA Safe Drinking Water Information System (SDWIS). Contaminant Maximum Contaminant Levels (MCLs) come from EPA's National Primary Drinking Water Regulations. The Water Safety Score weights health violations 40%, contaminant exceedances 30%, enforcement actions 20%, and monitoring violations 10%. Read the full IsWaterSafe methodology for the join logic and refresh cadence.
Frequently Asked Questions
How many public water systems does Pennsylvania have?
Pennsylvania has 5 public water systems registered in the EPA Safe Drinking Water Information System (SDWIS), serving an estimated 2,789,548 residents. The systems range from large municipal utilities serving entire metro areas to small community systems serving a few hundred customers.
Is Pennsylvania drinking water safe?
Pennsylvania's average Water Safety Score is 86 of 100. Pennsylvania runs 5.0 points above the U.S. average Water Safety Score of 81.0 — meaningfully better than the typical state, usually because of newer infrastructure or stronger state-level enforcement under EPA primacy. 2 of 5 Pennsylvania water systems (40%) have an open or recent EPA violation — well above the U.S. average. The concentration is typical of states with many small rural systems where compliance staffing is thin. An EPA Maximum Contaminant Level violation is a regulatory event, not a clinical diagnosis — see the IsWaterSafe disclaimer for the distinction.
Which contaminants matter most in Pennsylvania?
The most-detected contaminants flagged in EPA SDWIS for Pennsylvania are Chlorine (1 systems) and Gross Alpha (1 systems). These typically reflect either source-water characteristics — agricultural runoff for nitrate, geology for arsenic, industrial proximity for PFAS — or distribution-system effects like lead from service lines and disinfection byproducts.
Where can I find my Pennsylvania utility's official report?
Every community water system in Pennsylvania is required by the Safe Drinking Water Act to publish an annual Consumer Confidence Report (CCR) by July 1, listing every regulated contaminant detected and how it compared to the EPA Maximum Contaminant Level. CCRs are typically posted on each utility's website. The state's drinking water program (operating under EPA primacy) maintains a portal of CCR links and enforcement records.
How is Pennsylvania's data updated?
EPA refreshes SDWIS quarterly, and IsWaterSafe re-runs the Pennsylvania state and ranking pages against each new release. Last refreshed April 2026. Note that violations have a typical 60–90 day reporting lag from the date of detection.
Sources: EPA Safe Drinking Water Information System (SDWIS), EPA National Primary Drinking Water Regulations, EWG Tap Water Database. SDWIS and EPA regulations are U.S. government public domain. Cite as: "IsWaterSafe, Pennsylvania, April 2026 reading. Data: EPA SDWIS."
Last updated 2026-04-04 · 5 Pennsylvania systems tracked.
this entity is one of the data points covered by this site’s U.S. public drinking-water safety dataset. The detail above comes directly from the EPA Safe Drinking Water Information System (SDWIS); the context that follows situates the headline numbers against the broader distribution across U.S. public water systems.
The methodology behind every numeric value on this page is publicly documented on the the EPA Safe Drinking Water Information System (SDWIS) portal and described in detail on this site’s methodology page. Refresh cadence varies by underlying series; the page surfaces the as-of date for each number so readers can trace any figure back to the source release.
Practical use of this page is in combination with the comparison and ranking pages elsewhere on the site, which surface the same data for this entity’s peers within U.S. public water systems. A single-entity reading without peer context can be misleading when an entity is an outlier on one axis but typical on another.