PlainWater
Contaminants →
EPA SDWIS ~155K water systems EPA + UCMR5

Groundwater Rule

EPA SDWIS quarterly extract data for this analyte. Detection counts and health-based violation counts reflect the most recent federal release.

PlainWater home → About this data

EPA contaminant code: 0700

Total Violations
103,689
Systems Affected
7,907
Health-Based %
53.1%
Most Affected State
-

What this means

Groundwater Rule appears in EPA SDWIS with 103,689 recorded violations across 7,907 public water systems. Of those, 53.1% are classified as health-based, meaning the reading exceeded a federally enforceable Maximum Contaminant Level or a treatment-technique requirement rather than a monitoring or reporting lapse. Health-based violations are the subset that trigger formal corrective action and public notification, so the share is a useful signal of real-world exposure risk rather than paperwork drift. State-level concentration data is not consistently reported for this contaminant, so regional interpretation should lean on the system table below rather than state aggregates. Utilities listed below are ranked by cumulative violation count, so a higher rank reflects persistence in the record rather than a single spike; readers comparing systems should consider population served alongside violation count to gauge how many households were actually exposed.

Violation Type Split

Groundwater Rule violations broken down by EPA classification.

Health-based (53.1%) Monitoring/Reporting (46.9%)

Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement; monitoring/reporting violations are procedural.

Most Affected Water Systems

System State Violations Population
Hiawatha Water WV 518 63
Coal Mountain Water WV 500 80
Pinnacle Water Association WV 399 85
Stanton Hills Community PA 332 100
Milford Colony Inc MT 271 67
Burch Farms Country Market PA 264 25
Penns Creek Municipal Auth PA 263 725
Aqua PA Sun Valley PA 251 120
Paw Winola PA 251 130
Sunset MHP MO 244 80
Hoving Business Center MT 238 170
Green Frog, LLC. WV 230 60
Salem Heights Estate PA 224 62
Camino Real Regional Utility Authority NM 223 19,466
Green Camp Psd WV 217 44
G&t Country View Restaurant PA 210 25
Little Guys Baseball Club MO 207 150
Partners Produce ID 206 50
Bass Lake Park WV 194 40
Olympic Village PA 190 98
Bemis Campground WV 188 150
Stately Mansion Mobile Villa MO 181 100
Jonesboro Water System LA 177 6,231
Mountaineer Mini Mart WV 175 25
River Rest Campground WV 175 25
Phillips 66 #258 MO 173 300
Red Rock Water LLC ID 171 60
Midway Bowl Berkeley Springs WV 170 25
Stuarts Smokehouse WV 165 25
Gallatin Riverhouse Grill MT 158 50

Drinking Water Guides

Understanding Water Quality Data

What EPA SDWIS tracks, how violations are classified, and what MCLs mean.
PFAS in Drinking Water

What forever chemicals are, EPA testing results, and 2024 standards.
Is My Water Safe?

How to assess your local water quality and when to take precautions.

Frequently Asked Questions

What is Groundwater Rule in drinking water? ▼
Groundwater Rule is a contaminant tracked by the EPA under the Safe Drinking Water Act. It has caused 103,689 violations across 7,907 public water systems nationwide. 53.1% of these violations are health-based, meaning the contaminant exceeded Maximum Contaminant Levels (MCLs) or treatment technique requirements.
How many water systems have Groundwater Rule violations? ▼
7,907 public water systems across the United States have at least one Groundwater Rule violation recorded in the EPA SDWIS database.
Are Groundwater Rule violations dangerous? ▼
53.1% of Groundwater Rule violations are health-based, meaning the contaminant level exceeded safe limits set by the EPA. Health-based violations require corrective action by the water system. Not all violations indicate immediate health risk, but they signal that water quality standards were not met.
Which state has the most Groundwater Rule violations? ▼
State-level breakdown data is not available for this contaminant.
Where does this contaminant data come from? ▼
All violation data comes from the EPA Safe Drinking Water Information System (SDWIS), which tracks compliance for all public water systems regulated under the Safe Drinking Water Act. SDWIS records violations including Maximum Contaminant Level (MCL) exceedances, treatment technique failures, and monitoring/reporting issues.

Data Sources

Contaminant violation data from the EPA Safe Drinking Water Information System (SDWIS). Violations are categorized as health-based (Maximum Contaminant Level exceedances, treatment technique failures) or monitoring/reporting violations.

Related

Browse all → | Rankings →
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the EPA Safe Drinking Water Information System (SDWIS). Consult a qualified professional before making decisions based on this data.

Read our methodology - how this data is sourced, computed, and verified.

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.