Drinking Water Violations by State: 431,258 Public Water Systems in EPA Enforcement Data

What this page is. Safe Drinking Water Act compliance and enforcement data for every US state and the District of Columbia, retrieved directly from EPA’s Enforcement and Compliance History Online system. It covers 431,258 public water systems, 68,281 violations recorded in the most recent three-year window, 160,174 inspections and 10,371 formal enforcement actions. Enforcement patterns look different on the wastewater side, covered in our breakdown of Clean Water Act violations by state.

Read the limitation before the ranking. The state variation in this data is driven substantially by how each state primacy agency designates and reports violations, not only by how clean its water is. North Carolina reports zero serious violators across 23,642 systems. West Virginia reports 348 across 4,389. That is a reporting and enforcement difference as much as a water quality difference, and any state ranking built from this data inherits it. This page publishes the ranking and the caveat together rather than one without the other.

What the table shows

• EPA’s system holds records for 431,258 public water systems across the 50 states and the District of Columbia.
• 3,340 of those are flagged as serious violators, a national rate of 0.77 percent.
• 68,281 violations were recorded in the most recent three-year window, and 24,549 are currently open.
• States recorded 160,174 inspections, an average of 0.37 inspections per system.
• Formal enforcement actions totalled 10,371, or 24.0 per 1,000 systems. Informal actions totalled 71,494, roughly seven times as many.
• Serious violator rates range from 7.93 percent in West Virginia to zero in North Carolina and Hawaii.
• Four states report one or zero serious violators despite each having more than 1,300 systems, which indicates a designation practice difference rather than near-perfect compliance.
• The count of 431,258 includes transient non-community systems such as campgrounds and roadside businesses. It is roughly nine times the approximately 48,000 community water systems EPA counts for infrastructure funding purposes.

Every state and DC

Ranked by serious violator rate. Violations per system uses the three-year violation count. Read alongside the limitations section.

Rank	State	Systems	Serious violators	Rate	Violations (3 yr)	Per system	Inspections	Formal actions
1	District of Columbia	19	5	26.32%	11	0.58	16	0
2	West Virginia	4,389	348	7.93%	719	0.16	979	15
3	New Mexico	2,852	98	3.44%	885	0.31	1,251	89
4	Kansas	1,695	51	3.01%	653	0.39	998	11
5	Florida	20,137	522	2.59%	3,062	0.15	5,663	181
6	Louisiana	5,161	129	2.50%	725	0.14	1,467	122
7	Alaska	3,749	92	2.45%	855	0.23	1,521	10
8	Arizona	4,419	95	2.15%	1,328	0.30	1,831	92
9	Nevada	1,492	32	2.14%	354	0.24	712	5
10	Idaho	4,491	94	2.09%	1,363	0.30	2,155	26
11	Texas	16,600	308	1.86%	5,041	0.30	7,453	412
12	Oregon	6,127	91	1.49%	1,997	0.33	2,777	69
13	Oklahoma	5,742	78	1.36%	1,131	0.20	1,821	469
14	Maine	6,466	66	1.02%	1,234	0.19	2,227	94
15	Indiana	10,076	86	0.85%	2,588	0.26	4,739	144
16	Illinois	27,254	216	0.79%	2,724	0.10	6,110	93
17	New Jersey	14,907	101	0.68%	1,968	0.13	4,028	160
18	Georgia	5,674	38	0.67%	1,219	0.21	2,547	35
19	Wyoming	1,916	12	0.63%	436	0.23	823	109
20	Colorado	5,115	31	0.61%	1,373	0.27	2,411	126
21	Pennsylvania	22,959	138	0.60%	5,229	0.23	8,834	181
22	Montana	4,923	29	0.59%	1,276	0.26	2,502	41
23	Ohio	16,352	96	0.59%	2,180	0.13	4,960	409
24	Missouri	6,027	34	0.56%	1,849	0.31	3,051	55
25	Michigan	27,340	150	0.55%	4,044	0.15	12,155	223
26	Rhode Island	1,135	6	0.53%	214	0.19	491	15
27	Utah	2,234	11	0.49%	628	0.28	1,209	63
28	Alabama	1,821	8	0.44%	270	0.15	594	4
29	South Dakota	1,699	7	0.41%	227	0.13	755	4
30	Washington	9,966	39	0.39%	1,906	0.19	4,464	235
31	Maryland	8,045	31	0.39%	997	0.12	3,498	0
32	Tennessee	4,991	18	0.36%	406	0.08	834	57
33	Connecticut	11,230	39	0.35%	1,391	0.12	2,665	44
34	Vermont	4,415	15	0.34%	672	0.15	1,500	19
35	New Hampshire	4,370	13	0.30%	839	0.19	2,763	4
36	California	18,834	52	0.28%	2,552	0.14	8,036	2,079
37	Iowa	5,355	14	0.26%	732	0.14	1,971	33
38	New York	26,704	62	0.23%	3,977	0.15	9,704	983
39	Nebraska	2,897	6	0.21%	372	0.13	1,473	16
40	Mississippi	3,251	6	0.18%	819	0.25	1,246	18
41	Kentucky	2,199	4	0.18%	154	0.07	445	20
42	Arkansas	4,247	6	0.14%	458	0.11	1,081	143
43	Virginia	9,075	12	0.13%	1,203	0.13	3,238	33
44	North Dakota	1,642	2	0.12%	186	0.11	599	4
45	Wisconsin	24,877	25	0.10%	2,156	0.09	12,869	99
46	Minnesota	21,499	21	0.10%	527	0.02	7,252	64
47	Delaware	1,362	1	0.07%	109	0.08	553	3
48	Massachusetts	3,597	1	0.03%	469	0.13	1,763	576
49	South Carolina	6,055	1	0.02%	330	0.05	1,767	53
50	Hawaii	234	0	0.00%	15	0.06	139	3
51	North Carolina	23,642	0	0.00%	2,428	0.10	6,234	2,628

Source: US EPA Enforcement and Compliance History Online, Safe Drinking Water Act services, retrieved 25 September 2026. Rates calculated by The Plumbing Brief.

Sourced figures

1. Public water systems in EPA’s system: 431,258. Source: US EPA ECHO, SDWA services, 25 September 2026.
2. Serious violators: 3,340, a national rate of 0.77 percent. Source: US EPA ECHO.
3. Violations in the three-year window: 68,281. Source: US EPA ECHO.
4. Currently open violations: 24,549. Source: US EPA ECHO.
5. Inspections recorded: 160,174, or 0.37 per system. Source: US EPA ECHO.
6. Formal enforcement actions: 10,371, or 24.0 per 1,000 systems. Source: US EPA ECHO.
7. Informal enforcement actions: 71,494, about 6.9 times the number of formal actions. Source: US EPA ECHO.
8. Highest serious violator rate among states with more than 1,000 systems: West Virginia, 7.93 percent (348 of 4,389). Source: US EPA ECHO.
9. Next highest: New Mexico 3.44 percent, Kansas 3.01 percent, Florida 2.59 percent. Source: US EPA ECHO.
10. North Carolina records zero serious violators across 23,642 systems. Source: US EPA ECHO.
11. South Carolina records one across 6,055 systems, Massachusetts one across 3,597, and Delaware one across 1,362. Source: US EPA ECHO.
12. The District of Columbia shows the highest headline rate at 26.32 percent, but from only 19 systems. Source: US EPA ECHO.
13. EPA counts approximately 48,000 community water systems for infrastructure funding purposes, a different and much smaller universe. Source: US EPA, 2025 Update to the 7th DWINSA.
14. National drinking water infrastructure need: 625 billion dollars over 20 years. Source: US EPA, 7th DWINSA.

What we calculated

Derived finding 1: four states report one or zero serious violators

Formula. Identify states with more than 1,300 systems and one or fewer serious violators.

Finding. North Carolina (23,642 systems, zero), South Carolina (6,055, one), Massachusetts (3,597, one) and Delaware (1,362, one) all report at or below one serious violator. Across those four states that is one designation across 34,656 systems. West Virginia, with 4,389 systems, reports 348.

Inputs. US EPA ECHO SDWA services.

Limitations. This finding identifies a pattern in the data. It does not establish that any state is under-designating, and it is not evidence that water is unsafe in those states or safe in West Virginia. Serious violator designation follows a federal definition applied by state primacy agencies, and application varies.

Derived finding 2: informal enforcement outnumbers formal by about seven to one

Formula. Informal enforcement actions divided by formal enforcement actions, nationally.

Calculation. 71,494 divided by 10,371 equals approximately 6.9.

Finding. For every formal enforcement action taken under the Safe Drinking Water Act, roughly seven informal actions are recorded. Enforcement in this programme is overwhelmingly conducted through informal channels.

Inputs. US EPA ECHO SDWA services.

Limitations. Formal and informal actions are not equivalent instruments and the ratio should not be read as a measure of leniency. Recording practice for informal actions varies between primacy agencies.

Derived finding 3: inspection coverage is roughly one visit per three systems

Formula. Recorded inspections divided by systems.

Calculation. 160,174 divided by 431,258 equals 0.37.

Finding. Across the dataset there are 0.37 recorded inspections per public water system, roughly one inspection for every three systems in the period covered.

Inputs. US EPA ECHO SDWA services.

Limitations. The inspection count and the system count may cover different periods within ECHO, so this ratio is indicative rather than an annual inspection rate. Small transient systems are inspected on different schedules from large community systems, and the denominator is dominated by small systems.

Derived finding 4: the denominator problem in every published water violation statistic

Formula. Compare the ECHO system count against EPA’s community water system count.

Calculation. 431,258 against approximately 48,000, a ratio of about nine to one.

Finding. Statistics expressed as a share of “US water systems” differ by nearly an order of magnitude depending on whether they use all public water systems or only community water systems. A violation rate calculated on the larger denominator will look nine times better than the same violations expressed against community systems.

Inputs. US EPA ECHO; US EPA 2025 DWINSA update.

Limitations. The two counts come from different EPA systems and are not maintained for the same purpose, so the ratio is approximate. It is included to show why published percentages disagree, not to correct either figure.

How this report was built

Methodology

Source. Every figure was retrieved directly from EPA’s ECHO Safe Drinking Water Act REST services, one query per state, on 25 September 2026. No figure is taken from secondary reporting.

Fields used. System counts, serious violator counts, current violations, three-year violations, inspections, and formal and informal enforcement actions, as returned by the service.

Calculated columns. Serious violator rate, violations per system, inspections per system and the formal-to-informal ratio are calculated here, with formulas stated.

Why the caveat leads. A state ranking on this data will be read as a water quality ranking. It is not one. The caveat is placed above the table deliberately.

Last updated. 25 September 2026. ECHO updates continuously, so figures retrieved on a later date will differ.

Data limitations

• State differences reflect enforcement and reporting practice as much as water quality. Serious violator designation is applied by state primacy agencies and varies widely.
• The system count includes transient non-community systems such as campgrounds, rest stops and roadside businesses. It is not a count of municipal utilities.
• Small jurisdictions produce unstable rates. The District of Columbia’s 26.32 percent comes from 19 systems and five designations.
• A violation is a recorded compliance event, which includes monitoring and reporting failures as well as health-based exceedances. This page does not separate the two.
• ECHO is a live system. Counts change as states submit data, and late reporting is common.
• Inspection and system counts may cover different periods within ECHO, so per-system inspection figures are indicative.
• Nothing on this page describes the safety of any individual water supply. For that, consult the supplier’s Consumer Confidence Report and your state primacy agency.

Source quality ranking

Tier 1. US EPA Enforcement and Compliance History Online, Safe Drinking Water Act REST services. US EPA 2025 Update to the 7th DWINSA. US EPA 7th DWINSA.

Tier 2. None used.

Tier 3. None used.

Excluded. Secondary summaries of EPA violation data and any state ranking that does not disclose the designation-practice caveat.

If you quote one number

• EPA holds records for 431,258 public water systems, about nine times the number of community water systems usually cited.
• 68,281 drinking water violations were recorded in the most recent three-year window, and 24,549 remain open.
• North Carolina reports zero serious violators across 23,642 systems. West Virginia reports 348 across 4,389.
• For every formal enforcement action there are about seven informal ones.
• There is roughly one recorded inspection for every three public water systems.

Summary for reporters

EPA enforcement records cover 431,258 public water systems across the 50 states and the District of Columbia, of which 3,340 are flagged as serious violators, a national rate of 0.77 percent, according to data retrieved from the agency’s Enforcement and Compliance History Online system on 25 September 2026. The records show 68,281 violations in the most recent three-year window, 24,549 of them still open, alongside 160,174 inspections and 10,371 formal enforcement actions. Informal enforcement actions outnumber formal ones by roughly seven to one. State-level rates range from 7.93 percent in West Virginia to zero in North Carolina, which records no serious violators across 23,642 systems. That spread reflects differences in how state primacy agencies apply and report the serious violator designation as much as differences in water quality, and state comparisons drawn from this data should carry that caveat.

Angles this supports

1. One state reports zero serious water violators across 23,642 systems
2. EPA records 68,281 drinking water violations, a quarter still open
3. Why drinking water violation rankings measure enforcement, not water
4. For every formal water enforcement action there are seven informal ones
5. There is one inspection for every three public water systems

Download the data

Every figure in the table above is published as a CSV under a Creative Commons Attribution 4.0 licence. Attribution: The Plumbing Brief.

All 51 jurisdictions with systems, violations, inspections and enforcement (CSV)

Questions this answers

How many public water systems are there in the United States? EPA’s ECHO system holds records for 431,258 across the 50 states and DC. That includes transient non-community systems. EPA counts approximately 48,000 community water systems for funding purposes.

How many drinking water violations are there? 68,281 in the most recent three-year window, with 24,549 currently open, per EPA ECHO on 25 September 2026.

Which state has the most drinking water violations? By serious violator rate among states with more than 1,000 systems, West Virginia at 7.93 percent. By raw three-year violation count, Texas at 5,041. These measure different things.

Which state has the fewest? North Carolina reports zero serious violators across 23,642 systems, and Hawaii zero across 234. Those figures reflect designation practice and should not be read as evidence of the cleanest water.

Does a violation mean the water is unsafe? No. A recorded violation includes monitoring and reporting failures as well as health-based exceedances. This page does not separate the two.

Why do state comparisons vary so much? Because the serious violator designation is applied by state primacy agencies and practice differs. The variation between states is partly enforcement culture, not only water quality.

How often are water systems inspected? There are 160,174 recorded inspections against 431,258 systems, about 0.37 per system. Large community systems are inspected more frequently than small transient ones.

How much enforcement actually happens? 10,371 formal actions and 71,494 informal ones, so about 24 formal actions per 1,000 systems.

Where does this data come from? EPA’s Enforcement and Compliance History Online system, queried state by state through its Safe Drinking Water Act REST services.

How do I check my own water supply? This page is national and state-level data. For an individual supply, read your water supplier’s Consumer Confidence Report and contact your state primacy agency.

Last reviewed: 2026-09-25.

How to cite this report

The Plumbing Brief, “Drinking Water Violations by State: 431,258 Public Water Systems in EPA Enforcement Data”, https://theplumbingbrief.com/drinking-water-violations-by-state/, accessed [date].