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Herndon, VA · 1,146,214 people served · EPA data 2021–2026

Tap water quality in Herndon, Virginia

Herndon's water systems logged zero health-based EPA violations in 2021–2026 — water that met every federal health standard on record. Day-to-day quality still varies with pipes and plumbing, but the municipal record here is clean.

BGood
Herndon water grade: B
Good — our A–F grade from this city's EPA compliance record, relative to Virginia and the nation. How we grade →
Health-based violations, 2021–20260
Federal health standardsall met
Fairfax County Water Authority1,121,613 served
Herndon, Town Of24,601 served
Virginia quality rank#29 / 51 (83.0/100)
Virginia avg hardness120 PPM (moderately hard)
Want to know what's actually in your Herndon water?

Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.

Test your water at home

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Herndon tap water FAQ

Is tap water safe to drink in Herndon?

Herndon's community water systems reported no health-based EPA violations in 2021–2026, meaning the water met federal health standards throughout. Home plumbing (especially pre-1986 lead solder or service lines) can still affect what reaches your glass — a home test settles it.

Who supplies Herndon's water?

Fairfax County Water Authority (serving about 1,121,613 people); Herndon, Town Of (serving about 24,601 people). Data: EPA Safe Drinking Water Information System, July 2026.

How hard is the water in Herndon?

City-level hardness isn't published in a single federal dataset, but Virginia averages 120 PPM — "moderately hard" on the USGS scale. Your utility's water quality report lists Herndon's exact hardness, or a $10 test strip tells you in a minute. If it comes back over 120 PPM, see our water softener guidance in the purification calculator.

Do I need a water filter in Herndon?

The municipal record is clean, so filtering in Herndon is about taste, hardness and your own plumbing rather than compliance. A carbon filter fixes chlorine taste; test first if your home predates 1986 (lead solder era).

Want to know what's actually in your Herndon water?

Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.

Test your water at home

We may earn a commission if you request quotes through this link. It costs you nothing and never affects the data we publish.