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U.S. public record

The census of U.S. public water systems

142,891 active systems serving 349.3M people — every one an indexable public-record page, from EPA SDWIS/ECHO data.

Browse water systemsRankings
Active systems
Very high≥ 6,000
High3,000–6,000
Moderate1,000–3,000
Lower< 1,000

Active public water systems

142,891

Population served (reported)

349.3M

Cumulative across systems

Community systems (CWS)

49,378

Serve residents year-round

Groundwater-sourced

90.4%

Incl. purchased groundwater

Dataset updated . Source: EPA SDWIS/ECHO, refreshed quarterly.

Largest U.S. water systems

Full ranking →
The 15 largest active U.S. public water systems by population served
#Water systemStateCountyPopulation servedTypeSource
1New York City SystemNew YorkRichmond + 4 more8,271,000CommunitySurface water
2Los Angeles-City, Dept. of Water & PowerCaliforniaLos Angeles3,875,566CommunitySurface water
3City of HoustonTexasHarris2,970,543CommunitySurface water
4ChicagoIllinoisCook2,721,308CommunitySurface water
5San Antonio Water SystemTexasBexar2,643,729CommunityPurchased surface water
6MWRAMassachusettsSuffolk2,580,000CommunitySurface water
7Mdwasa - Main SystemFloridaMiami-Dade2,377,460CommunityGroundwater
8Washington Suburban Sanitary CommissionMarylandMontgomery1,900,000CommunitySurface water
9Phoenix City ofArizonaMaricopa1,695,000CommunitySurface water
10City of BaltimoreMarylandBaltimore city1,600,000CommunitySurface water
11Philadelphia Water DepartmentPennsylvaniaPhiladelphia1,600,000CommunitySurface water
12Las Vegas Valley Water DistrictNevadaClark1,539,277CommunityPurchased surface water
13East Bay MUDCaliforniaAlameda1,442,800CommunitySurface water
14San Diego, City ofCaliforniaSan Diego1,385,379CommunitySurface water
15Dallas Water UtilityTexasDallas1,356,479CommunitySurface water

Water systems by state

Alabama576Alaska1,322Arizona1,769Arkansas853California7,479Colorado2,207Connecticut2,363Delaware494District of Columbia12Florida5,197Georgia2,375Hawaii136Idaho1,961Illinois3,872Indiana3,969Iowa1,828Kansas1,041Kentucky437Louisiana1,121Maine1,862Maryland2,992Massachusetts1,636Michigan10,599Minnesota6,465Mississippi1,133Missouri2,943Montana2,378Nebraska1,226Nevada643New Hampshire2,450New Jersey3,496New Mexico1,165New York8,167North Carolina5,087North Dakota403Ohio3,854Oklahoma1,254Oregon2,536Pennsylvania7,217Rhode Island465South Carolina1,392South Dakota699Tennessee1,383Texas7,078Utah1,133Vermont1,357Virginia2,420Washington4,705West Virginia791Wisconsin11,056Wyoming775

Data access

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