DATA-BACKED RANKINGS

Water quality rankings hub

Every page below pulls from EPA monitoring (UCMR5), Safe Drinking Water Information System violations, or structured city profiles we maintain for 135+ metros. Use this hub to navigate stories that are designed to rank in search and hold up to scrutiny.

UCMR5 · ppt vs EPA MCL

10 worst PFAS systems (UCMR5)

Water systems with the highest regulated PFAS above federal limits — compound-by-compound ppt and how many times over the MCL.

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City profiles · editorial

Highest THM / DBP risk cities

Cities where our profiles explicitly flag trihalomethanes, haloacetic acids, or disinfection byproducts — sorted by risk tier.

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Top 50 · all PFAS detections

Broad PFAS exposure ranking

Largest aggregate PFAS readings across utilities, including compounds without an EPA MCL yet.

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Lead · service lines

Worst lead risk cities

Cities with the highest documented lead-in-water risk from EPA context and our city-level flags.

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SDWIS compliance

Most EPA violations

Utilities and regions with the heaviest Safe Drinking Water Act violation histories we surface in rankings.

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State comparison

Worst states for water quality

State-level rollup of contamination pressure, violations, and infrastructure stress.

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METHODOLOGY

Rankings combine federal datasets with editorial city profiles. Pages like PFAS-over-MCL lists cite exact monitoring values; THM/DBP lists explain when we are inferring risk from keywords in our city database rather than re-ranking every utility nationally.

How we source and interpret data →