Nitrate In Drinking Water In Pennsylvania
What residents of Pennsylvania need to know about nitrate in drinking water — including how it enters water, which utilities have documented violations, and what steps to take.
Source: EPA SDWIS, Pennsylvania Department of Environmental Protection (PADEP), CDC · Last reviewed: 2025-01-01
Quick Answer
Is nitrate in drinking water a real concern in Pennsylvania?
Yes — Lancaster County and southcentral Pennsylvania have some of the most intensive agricultural land use in the Mid-Atlantic, generating documented nitrate issues in private wells.
Is this mostly a public-water issue, a private-well issue, or both?
Primarily private well users in agricultural counties; public water systems are monitored by PADEP and generally comply with the nitrate MCL.
What is the main reason residents should care?
Pennsylvania's farming heartland — Lancaster, Chester, York, and Adams Counties — has dense dairy, poultry, and crop operations generating significant nitrate loading. Private wells in these counties have documented exceedances of the 10 mg/L MCL.
Key Facts
| EPA Nitrate MCL | 10 mg/L as N |
| Lancaster County context | One of the most intensively farmed non-irrigated counties in the US |
| Primary source | Animal manure application, fertilizer, and septic systems in agricultural counties |
| Chesapeake Bay watershed | Agricultural nutrient reduction is a regulatory priority in PA |
| State oversight | Pennsylvania Department of Environmental Protection (PADEP) |
Why This Matters in Pennsylvania
Lancaster County, Pennsylvania, is one of the most productive non-irrigated agricultural counties in the United States, with a high density of dairy farms, poultry operations, and crop fields. Nitrate from animal manure, fertilizer, and septic systems has been documented in private wells across the county and in neighboring Chester, York, and Adams Counties. Pennsylvania is in the Chesapeake Bay watershed, and agricultural nutrient management — including nitrate reduction — is a regulatory priority. PADEP monitors public water supplies and provides private well testing guidance.
Critical — Infants Under 6 Months
Do not use tap water that exceeds 10 mg/L nitrate-nitrogen to prepare infant formula or feed infants under six months. Boiling will concentrate nitrate — do not boil. Use bottled water or a certified reverse osmosis system (NSF/ANSI 58) until the issue is resolved.
Pennsylvania Utilities With Nitrate Violation Records
The utilities listed below have at least one nitrate violation on record in EPA's SDWIS database. Violations may be open or resolved — see individual utility pages for current status and risk level.
Philadelphia Water Department
Philadelphia · 1,600,000 served
Pittsburgh Water & Sewer Auth
Pittsburgh · 520,000 served
Erie City Water Authority
Pennsylvania · 220,001 served
West View Water Authority
Pennsylvania · 200,000 served
Mawc Sweeney Plant
Pennsylvania · 143,000 served
Mawc Yough Plant
Pennsylvania · 133,000 served
Veolia Water
Pennsylvania · 110,000 served
Reading Area Water Authority
Reading · 95,100 served
North Wales Water Authority
Pennsylvania · 72,496 served
Capital Region Water
Pennsylvania · 66,540 served
How Nitrate Gets Into Drinking Water
Agricultural fertilizer and manure runoff
Nitrogen-based fertilizers and animal waste applied to Pennsylvania cropland can leach into groundwater or run off into surface water supplies. This is the dominant nitrate pathway in most agricultural regions.
Septic system effluent
Failing or poorly sited septic systems release nitrogen-rich wastewater near drinking water wells. Rural areas with high well density and aging septic infrastructure face elevated risk.
Concentrated animal feeding operations (CAFOs)
Large livestock facilities generate significant waste. Lagoon leaks and overapplication of manure to nearby fields can create localized nitrate hotspots in groundwater.
Natural geological deposits
In some regions, naturally occurring nitrogen compounds in soil and bedrock contribute background nitrate levels to groundwater independent of agricultural activity.
Who Should Pay Closest Attention
Farming families with private wells in Lancaster, Chester, York, Adams, and surrounding counties should test their well water for nitrate annually. Households with infants are at the greatest health risk from nitrate exceeding 10 mg/L.
Households with infants under six months
Pregnant residents
Private well owners in agricultural areas
Households near livestock operations or CAFOs
Rural residents on shallow groundwater wells
Households with older or failing septic systems nearby
How to Check Your Situation in Pennsylvania
- 1
Identify your water utility. Use the ZIP lookup below or browse the Pennsylvania utility directory on this site.
- 2
Read your utility's page on this site to see its current risk level and any open nitrate violations.
- 3
Review your utility's most recent Consumer Confidence Report (CCR) — mailed annually or available on the utility's website. It must disclose any MCL exceedances.
- 4
If you are on a private well, arrange testing at a Pennsylvania Department of Environmental Protection (PADEP)-certified lab. Your state health department maintains a list of certified labs. Annual testing is recommended in agricultural areas.
- 5
If you have an infant under six months, use bottled water or a certified RO system (NSF/ANSI 58) immediately as a precautionary measure — do not wait for test results if you are in a high-risk area.
- 6
If your utility issues a nitrate exceedance notice, follow their guidance and do not use tap water for infants until the issue is resolved.
Treatment Options
Carbon filters and boiling do not remove nitrate. Only the options below are effective.
NSF/ANSI Standard 58 — Reverse Osmosis
RO systems certified to NSF/ANSI 58 reduce nitrate by 85–95% at the point of use. Under-sink installation required. The most practical residential option for nitrate concerns.
Distillation
Distillation units effectively remove nitrate along with most other dissolved contaminants. Suitable for drinking and cooking water — not whole-house use.
Anion Exchange
Ion exchange systems designed for nitrate removal exchange nitrate ions for chloride on a resin bed. Effective as a point-of-entry system; requires periodic regeneration and monitoring.
Carbon filters do NOT remove nitrate
Standard pitcher filters, faucet filters, and under-sink carbon units — including those certified NSF/ANSI 42 or 53 — do not remove nitrate. Do not use these for nitrate reduction.
Frequently Asked Questions
Related Pages
Nitrate — National Overview
All U.S. utilities with nitrate records
Pennsylvania State Overview
All utilities and water quality data
Lead in Drinking Water
A separate but common concern
Reverse Osmosis Guide
Removes 85–95% of nitrate
Well Water Guide
Private well testing and safety
All Contaminants
Complete reference library
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.