Nickel in drinking water
672 active public water systems in 37 states had a Nickel violation in the past three years, and 9 have one that is still unresolved.
You are on Tapcensus, an independent guide to the EPA compliance records of every public water system in the United States. This page explains Nickel and lists the water systems whose records include a related violation. It does not show measured levels.
Is Nickel in the records for your water system?
Enter a ZIP code, town, or street address to see the water systems that serve your area, their status, and which rules and contaminants appear in their violations.
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What it is and where it comes from
Nickel is a naturally occurring metal that leaches from rock and soil into groundwater and surface water. Industrial sources include metal plating, battery manufacturing, and mining operations. Nickel can also leach from faucets, fittings, and stainless steel plumbing components, particularly in low-pH water. It was added to the NPDWR framework as part of the Phase II rule.
Health effects
Chronic oral exposure to nickel in drinking water is associated with cardiovascular and kidney effects. Nickel compounds are classified as known human carcinogens (Group A) by IARC for inhalation; the oral carcinogenicity evidence is less established. Individuals with nickel sensitivity may also experience dermatological reactions.
The standard and what a violation means
EPA limit: 0.1 mg/L (100 ppb).
Water systems with a Nickel violation, by state
Active public water systems that reported at least one related violation to EPA in the past three years. Each state links to the list of its affected systems.
| State | Systems with violations, 3 yr | Share of active systems | Unresolved |
|---|---|---|---|
| Pennsylvania | 119 | 2% | 0 |
| Georgia | 61 | 3% | 0 |
| New York | 54 | 1% | 0 |
| Michigan | 51 | 0% | 0 |
| Colorado | 29 | 1% | 4 |
| Indiana | 29 | 1% | 0 |
| West Virginia | 28 | 4% | 0 |
| New Jersey | 25 | 1% | 0 |
| Montana | 22 | 1% | 0 |
| Wyoming | 22 | 3% | 0 |
| Washington | 21 | 0% | 0 |
| Idaho | 20 | 1% | 1 |
| Oklahoma | 20 | 2% | 0 |
| California | 19 | 0% | 0 |
| Connecticut | 17 | 1% | 0 |
| Virginia | 15 | 1% | 0 |
| Oregon | 13 | 1% | 0 |
| Maine | 12 | 1% | 0 |
| Wisconsin | 11 | 0% | 0 |
| Utah | 10 | 1% | 0 |
| Illinois | 9 | 0% | 0 |
| Massachusetts | 9 | 1% | 2 |
| Alaska | 8 | 1% | 0 |
| Nevada | 8 | 1% | 0 |
| Vermont | 7 | 1% | 2 |
| North Carolina | 6 | 0% | 0 |
| Maryland | 5 | 0% | 0 |
| Minnesota | 5 | 0% | 0 |
| Alabama | 4 | 1% | 0 |
| Rhode Island | 3 | 1% | 0 |
| Arizona | 2 | 0% | 0 |
| Florida | 2 | 0% | 0 |
| South Dakota | 2 | 0% | 0 |
| Hawaii | 1 | 1% | 0 |
| Kentucky | 1 | 0% | 0 |
| North Dakota | 1 | 0% | 0 |
| New Mexico | 1 | 0% | 0 |
Largest water systems with a Nickel violation
The ten biggest systems, by people served, whose records include a related violation in the past three years.
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Aqua PA Main System Montgomery County |
822,600 | 6 | 0 | |
|
Aquarion-Eastern Fairfield County Beacon Falls, Bridgeport, Darien and 17 more · Fairfield County |
351,756 | 2 | 0 | |
|
Corona, City of Corona · Riverside County |
169,380 | 6 | 0 | |
|
City of Sunnyvale Sunnyvale · Santa Clara County |
157,566 | 5 | 0 | |
|
GW Santa Cruz Water CO Maricopa · Pinal County |
84,000 | 7 | 0 | |
|
Tigard, City of Washington County |
62,500 | 2 | 0 | |
|
Greater Johnstown WA Riverside Cambria County |
49,500 | 7 | 0 | |
|
Greenlawn Water District Huntington (t) · Suffolk County |
42,000 | 3 | 0 | |
|
Winslow Twp Dmu Winslow Twp · Camden County |
39,174 | 6 | 0 | |
|
Bullhead City Mohave Bullhead City · Mohave County |
36,330 | 13 | 1 |
About this data
A system is counted once if any of its violations in the past three years involved Nickel, including monitoring and reporting lapses. Rules violated and status in the systems table are for the whole system, not Nickel alone. Counts cover active systems in all 50 states and the District of Columbia.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet.