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States with the Most Public Water Systems

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All states ranked by total number of regulated public water systems serving their populations.

What This Ranking Tells Us

The number of public water systems reflects both population size and how water delivery is organized. States with many systems often have fragmented water infrastructure, numerous small community systems rather than large consolidated utilities. Texas leads the nation due to its vast geography, many small communities, and independent water districts. More systems can mean more oversight challenges, as small systems often lack the resources for advanced treatment and monitoring compared to large urban utilities.

This page ranks all 50 U.S. states and territories on a single indicator - systems - drawn directly from the EPA Safe Drinking Water Information System (SDWIS). The ranking draws on 51 state records in the current dataset, ordered descending (highest count at the top) by the underlying federal count.

The top of the table is led by Texas with a reported value of 4,587, followed by California (3,077) and Washington (2,397). The bottom of the ranking ends with Rhode Island at 92, illustrating the spread across the federal record.

A state's position depends on underlying geography, industrial history, population, and the density of reporting entities, not on a simple "cleaner" or "dirtier" label. Use the links in the table to open each state's full environmental profile and view county-level breakdowns, individual facility records, and violation history. Data source: EPA Safe Drinking Water Information System (SDWIS). All figures are as-filed and not weighted for toxicity or exposure.

States with the Most Public Water Systems: top 15

Ranked by systems - full table below

systems

What this shows Rankings reflect reported federal totals, shaped by each state's geography, industrial history and population, not a direct measure of health risk or water safety.

Source EPA Safe Drinking Water Information System (SDWIS) As of most recent EPA release
#1 Texas 4,587 systems #2 California 3,077 systems #3 Washington 2,397 systems
# State Systems
1 Texas TX 4,587
2 California CA 3,077
3 Washington WA 2,397
4 New York NY 2,201
5 North Carolina NC 1,965
6 Pennsylvania PA 1,787
7 Illinois IL 1,783
8 Georgia GA 1,715
9 Missouri MO 1,666
10 Florida FL 1,516
11 Michigan MI 1,433
12 Colorado CO 1,109
13 Ohio OH 1,094
14 Iowa IA 1,077
15 Virginia VA 1,054
16 Minnesota MN 993
17 Mississippi MS 990
18 Wisconsin WI 977
19 Arizona AZ 956
20 Oregon OR 938
21 Oklahoma OK 883
22 Kansas KS 858
23 Louisiana LA 835
24 Montana MT 809
25 Idaho ID 767
26 Indiana IN 718
27 New Hampshire NH 678
28 Arkansas AR 667
29 New Jersey NJ 619
30 Nebraska NE 596
31 New Mexico NM 590
32 Massachusetts MA 564
33 Utah UT 559
34 South Carolina SC 557
35 Alabama AL 543
36 South Dakota SD 512
37 Connecticut CT 503
38 Maryland MD 456
39 Tennessee TN 453
40 West Virginia WV 424
41 Alaska AK 404
42 Puerto Rico PR 402
43 Vermont VT 380
44 Kentucky KY 376
45 Maine ME 361
46 North Dakota ND 318
47 Wyoming WY 316
48 Nevada NV 228
49 Delaware DE 209
50 Hawaii HI 118
51 Rhode Island RI 92

Source: EPA Safe Drinking Water Information System (SDWIS).

Frequently Asked Questions

What qualifies as a public water system?

The EPA defines a public water system as one that provides water for human consumption through pipes or other infrastructure to at least 15 service connections or serves at least 25 people for at least 60 days a year. This includes community water systems (serving year-round residents), non-transient non-community systems (like schools), and transient non-community systems (like campgrounds).

Are more water systems better or worse?

Having many small systems creates oversight challenges, each system needs monitoring, treatment, and operator certification. Large consolidated systems benefit from economies of scale, professional staff, and better equipment. However, a single large system failure affects more people. The ideal is adequate-sized systems with proper resources, regardless of total count.

Explore More Rankings

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What to do with this ranking

Use the leaders here as a starting point, then check your own state's full record.

  • Texas tops this list at 4,587 systems - see its full environmental profile, not just this one metric. View Texas
  • This single indicator doesn't capture the full picture. Compare against most tri facilities for a different angle. Most TRI Facilities
  • Look up any state directly to see its complete facility, water, and Superfund record in one place. Browse all states

Rankings reflect reported federal data for a single indicator; a high or low rank does not by itself measure overall environmental quality or health risk.

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

According to the U.S. Environmental Protection Agency, this ranking is drawn from PlainEnviro's database of more than 25,000 EPA-tracked facilities and thousands of Safe Drinking Water Information System and Superfund National Priorities List records compiled since federal reporting began under the Emergency Planning and Community Right-to-Know Act in October 1986; see our methodology for the full data-source citations and refresh cadence.

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Data sourced from U.S. EPA environmental datasets. See our methodology for details. Retrieved and formatted by PlainEnviro Editorial

Every figure on PlainEnviro is rendered directly from EPA environmental compliance data, no number is typed in by an editor. Rankings are computed directly from EPA data. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.