Data hub · 20 rankings

U.S. water rankings

The real numbers behind America's water — which states and cities have the cleanest and worst tap water, the most violations and lead, the heaviest use, and the deepest drought. Every ranking is built from federal data and cites its source.

Drawn from 48,769 active community water systems serving 330 million people (EPA SDWIS), USGS water-use estimates, and the U.S. Drought Monitor.

Drinking-water safety

States With the Most Drinking-Water Violations

Community water systems with at least one health-based Safe Drinking Water Act violation since 2016, by state.

#1 Texas · 1,723 systems

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States Where the Most Water Systems Are in Violation

Share of each state's community water systems with a health-based violation since 2016 — a size-adjusted look at drinking-water trouble.

#1 Oklahoma · 73.9%

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States With the Safest Community Tap Water

The states where the smallest share of community water systems have a recent health-based violation.

#1 Hawaii · 6%

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States With the Most Lead Action-Level Exceedances

Community water systems whose most recent 90th-percentile sample exceeded EPA's 0.015 mg/L lead action level.

#1 Pennsylvania · 390 systems

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America's Largest City Water Systems

The biggest community water systems we profile, by population served — the utilities that deliver tap water to the most Americans.

#1 Los Angeles · 7,751,132 served

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Big Cities With the Lowest Lead Levels

Among large city water systems, those with the lowest most-recent 90th-percentile lead result — the cleanest big-city tap water for lead.

#1 San Diego · 0 ppb

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Big Cities With the Highest Lead Levels

Large city water systems with the highest most-recent 90th-percentile lead result.

#1 Dayton · 470 ppb

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Contaminants

The Most Common Drinking-Water Contaminants

Which contaminants and rules drive the most health-based violations across U.S. community water systems.

#1 Lead · 5,736 systems

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Water use

States With the Highest Per-Capita Water Use

Public-supply withdrawals per person served each day — where households and the systems serving them use the most water.

#1 Idaho · 219 gpcd

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The Most Water-Efficient States

The states with the lowest public-supply withdrawals per person served — the most efficient water users.

#1 District of Columbia · 0 gpcd

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States That Withdraw the Most Water

Total water withdrawn for all uses — public supply, irrigation, and thermoelectric power — in millions of gallons per day.

#1 California · 28.8 Bgal/d

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States Most Reliant on Groundwater

Share of freshwater withdrawals that come from underground aquifers rather than rivers and reservoirs.

#1 Mississippi · 84%

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Drought & supply

The Most Drought-Stricken States Right Now

Share of each state's area currently in severe drought or worse (D2+) on the U.S. Drought Monitor.

#1 Delaware · 100%

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States With the Most Extreme Drought

Share of area in extreme or exceptional drought (D3–D4) — the most severe categories on the U.S. Drought Monitor.

#1 Nebraska · 50%

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Reuse

Top Water-Reuse States

The states recycling the largest share of their treated wastewater for beneficial use.

#1 Nevada · ~60%

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Global

Countries With the Least Access to Safe Drinking Water

The countries where the smallest share of people use safely managed drinking water, per WHO/UNICEF data.

#1 Central African Republic · 6.22%

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Where the Most People Lack Safe Drinking Water

The countries with the largest populations without safely managed drinking water — the scale of the global gap.

#1 India · 341.8M

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The Most Water-Stressed Countries

Countries withdrawing the largest share of their renewable internal freshwater each year — values above 100% mean they draw down reserves or depend on outside flows.

#1 Egypt, Arab Rep. · 7,750%

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Countries With the Least Freshwater Per Person

Renewable internal freshwater resources per capita — the countries with the scarcest natural water endowment.

#1 Kuwait · 0 m³

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Countries With the Best Access to Safe Drinking Water

The countries where nearly everyone uses safely managed drinking water.

#1 Gibraltar · 100%

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