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Groundwater Rule in U.S. Drinking Water

Health-based violation data for Groundwater Rule from EPA Safe Drinking Water Information System (SDWIS). Covers all community water systems with violations on record.

Groundwater Rule has been found in violation of EPA standards in 6,563 water systems across 47 states, with 25,637 total health-based violations recorded. The most affected states are New Mexico, Louisiana, Pennsylvania.

Health-Based Violation Records
25,637
Water Systems Affected
6,563
States Affected
47

Groundwater Rule is regulated under the EPA Safe Drinking Water Act, which sets enforceable Maximum Contaminant Levels (MCLs) and associated treatment technique requirements for public water systems. The EPA Safe Drinking Water Information System (SDWIS) tracks every recorded violation nationwide and links it back to the specific public water system (PWSID), violation type, and begin date.

Across the United States, PlainEnviro's joined extract contains 25,637 health-based violation records carrying Groundwater Rule (EPA code 0700) across 6,563 active community water systems in 47 states. Raw record counts are highest in New Mexico, Louisiana, Pennsylvania, with New Mexico accounting for 3,843 records across 369 systems. Health-effect prose is shown only when the official ECHO substance name matches a verified topic; otherwise the portal stays silent rather than inventing guidance.

A health-based violation does not mean residents were necessarily harmed, it means the contaminant exceeded the federal MCL in a compliance sample, triggering notification and remediation requirements. States and utilities maintain primary enforcement responsibility. To check the status of a specific water system, request its most recent Consumer Confidence Report or consult the EPA's Drinking Water Watch portal for the corresponding state.

Violations by State

States ranked by number of health-based violations for Groundwater Rule.

# State Violations Systems Affected
1 New Mexico 3,843 369
2 Louisiana 2,804 395
3 Pennsylvania 1,869 458
4 Alaska 770 159
5 Idaho 635 137
6 Missouri 572 199
7 Utah 571 185
8 Arizona 419 117
9 California 386 57
10 West Virginia 301 64
11 Washington 287 45
12 Colorado 251 76
13 Mississippi 235 91
14 Nevada 201 44
15 Wisconsin 191 89
16 Kansas 184 57
17 Oregon 158 33
18 Northern Mariana Islands 151 11
19 Montana 148 49
20 Wyoming 144 69
21 Indiana 141 37
22 New Hampshire 141 89
23 New York 136 36
24 Texas 102 35
25 South Dakota 87 47
26 Virginia 72 16
27 Maryland 71 11
28 Ohio 70 31
29 American Samoa 69 5
30 North Carolina 67 10
31 Michigan 64 33
32 Arkansas 54 7
33 Nebraska 54 12
34 Georgia 51 18
35 Tennessee 42 6
36 Connecticut 39 22
37 Iowa 36 18
38 New Jersey 33 12
39 Massachusetts 27 15
40 Florida 25 8
41 Illinois 22 6
42 Minnesota 13 9
43 Oklahoma 5 2
44 Kentucky 4 3
45 Alabama 3 1
46 North Dakota 2 1
47 Vermont 2 2

Most Affected Water Systems

Top 50 water systems by number of Groundwater Rule health-based violations.

Water System State Violations
PITHOLE WATER ASSOCIATION PA 102
CAMINO REAL REGIONAL UTILITY AUTHORITY NM 97
Commonwealth Utilities Corp (Saipan) MP 69
REGINA MDWCA NM 64
CUBA WATER SYSTEM NM 62
CEDAR SPRINGS COMMUNITY WATER ID 58
MCKEE BRIDGE MOBILE HOME PARK CA 57
KOBUK WATER SYSTEM AK 54
ROSA JOINT VENTURES WATER SYSTEM CO 50
BIA NORTH IDAHO ID 49
RIO DE ARENAS NM 49
CAPULIN MDWCA NM 48
GALLINA WATER SYSTEM NM 48
TORREON MDWCA NM 45
Pala North CA 44
CASAS ADOBES MDWCA NM 44
Aoa ASG AS 41
TOWN OF JONESBORO WATER SYSTEM LA 41
CHIPPEWAY PARK WATER ASSOCIATION NM 41
OJO FELIZ MDWCA NM 40
ECHO VALLEY MHP MD 40
PRAIRIE ROAD WATER DISTRICT LA 39
JEMEZ SPRINGS DWUA NM 38
TOWN OF FERRIDAY WATER SYSTEM LA 36
DESERT SUNRISE WATER USERS ASSOC NV 36
CORREO WATER ASSOCIATION NM 35
LORDSBURG WATER SUPPLY SYSTEM NM 34
SAN RAFAEL WATER & SANITATION DISTRICT NM 34
LOVING WATER SYSTEM NM 33
MAGDALENA VILLAGE OF NM 33
DONA ANA MDWCA NM 33
ASPEN RIDGE SUBD ID 32
RAMAH WATER & SANITATION DISTRICT NM 32
BIBO MUTUAL DOMESTIC WATER ASSOC NM 32
VILLAGE WATER SYSTEM LA 31
SUNSET ACRES WATER COMPANY NM 31
MOQUINO WATER SYSTEM NM 31
VILLAGE OF PALMETTO WATER SYSTEM LA 30
TOP OF THE WORLD WATER ASSOCIATION CORP NM 30
CEDAR RIDGE TRAILER PARK NM 30
RBE WATER ASSOCIATION INC PA 30
HOSANNA HEIGHTS WATER AR 29
RED ROCK WATER LLC ID 29
CITY OF LAKE PROVIDENCE WATER SYSTEM LA 29
VILLAGE OF BONITA WATER SYSTEM LA 29
SANTA CRUZ WATER ASSOCIATION NM 29
CLARENDON ACRES WATER CO PA 29
Duckwater NV 28
RANCHOS DE TAOS MDWCA NM 28
ARTESIA MUNICIPAL WATER SYSTEM NM 28

Frequently Asked Questions

Is Groundwater Rule in my water?

Groundwater Rule has been detected in violation of EPA health standards in 6,563 water systems across 47 states. To check your specific utility, look up your annual Consumer Confidence Report (CCR) - water systems are required to disclose all violations.

How many water systems have Groundwater Rule violations?

EPA SDWIS records show 6,563 community water systems with health-based Groundwater Rule violations, totaling 25,637 violations. These represent cases where the contaminant exceeded the EPA Maximum Contaminant Level (MCL).

Which states have the most Groundwater Rule violations?

The states with the most Groundwater Rule violations are: New Mexico (3,843 violations), Louisiana (2,804 violations), Pennsylvania (1,869 violations), Alaska (770 violations), Idaho (635 violations).

Explore More

Water Quality Home → All Contaminants → Browse by State →

About This Data

Violation data is from the EPA Safe Drinking Water Information System (SDWIS). Only health-based violations are shown, these include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. Monitoring and reporting violations are excluded. Data may not reflect the most current enforcement actions.

Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services

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

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Data sourced from the U.S. Environmental Protection Agency (EPA). See our methodology for details. Retrieved and formatted by PlainEnviro