TapGraded
B

FAIRFAX COUNTY WATER AUTHORITY

Herndon, VA · 1,121,613 served

FAIRFAX COUNTY WATER AUTHORITY serves 1,121,613 people in Herndon, VA. It has 0 health-based violations in the last 5 years. TapGraded gives this system a B.

Score breakdown

Health-based violations (5y)

0

Monitoring violations (5y)

0

Currently unaddressed

0

Overall score

80/100

Violation history (last 5 years)

No violations on record.

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Lead (Lead and Copper Rule)

EPA's current lead action level is 15 ppb (dropping to 10 ppb in 2027 under the Lead and Copper Rule Improvements).

90th-percentile lead sample 1.2 ppb
0 ppb EPA action level: 15 ppb

PFAS (UCMR5 occurrence data)

HFPO-DA (not detected) 0 ppt
0 ppt EPA MCL: 10 ppt
PFHxS (not detected) 0 ppt
0 ppt EPA MCL: 10 ppt
PFOS 5.7 ppt over limit
0 ppt EPA MCL: 4 ppt
PFOA 7.4 ppt over limit
0 ppt EPA MCL: 4 ppt
PFNA (not detected) 0 ppt
0 ppt EPA MCL: 10 ppt

System details

System type
Community water system
Water source
Surface water
Ownership
Local government
Service connections
281,686

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Frequently asked questions

Is Herndon, VA tap water safe to drink?

FAIRFAX COUNTY WATER AUTHORITY has 0 health-based violations in the last 5 years. TapGraded gives this system a B.

Does FAIRFAX COUNTY WATER AUTHORITY have lead in its water?

The most recent 90th-percentile lead sample is 1.2 ppb, versus the EPA action level of 15 ppb.

Has PFAS been detected in FAIRFAX COUNTY WATER AUTHORITY's water?

Yes — PFAS was detected at or above the EPA MCL for 2 of the tracked analytes.

Source: EPA SDWIS/ECHO · Data as of 2026Q2