Tap WaterIndex

← Herndon, VA

Tap water quality report

ZIP 20151 — Herndon, VA

EPA monitoring across the 2 water suppliers serving ZIP 20151 in Herndon, VA detected 33 contaminants. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier below, with the EPA limit for each.

2
water suppliers
1,456,421
people served
33
contaminants found

What was found in ZIP 20151

The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate-Nitrite
1614 µg/L 16%
of the EPA limit 10000 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 1787.5 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Nitrate
1610 µg/L 16%
of the EPA limit 10000 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Fluoride
800 µg/L 20%
of the EPA limit 4000 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Copper
190 µg/L 15%
of the EPA limit 1300 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 277.6 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
TTHM
63.305 µg/L 79%
of the EPA limit 80 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 63.765 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Chloroform
47.57 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 55.03 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Total Haloacetic Acids (HAA5)
40.7 µg/L 68%
of the EPA limit 60 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 54.6 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Barium
48.16 µg/L 2.4%
of the EPA limit 2000 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Dichloroacetic Acid
22.115 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 27.42 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Trichloroacetic Acid
17.5 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 25.765 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Nitrite
20 µg/L 2%
of the EPA limit 1000 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
1/2 SYR4
Bromodichloromethane
12.7 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Lead
1.09 µg/L 7.3%
of the EPA limit 15 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 10.775 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Bromate
8.9 µg/L 89%
of the EPA limit 10 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
1/2 SYR4
Dibromochloromethane
6.6695 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Gross Beta Particle Activity
5.55 pCi/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Monochloroacetic Acid
3.737 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 4.265 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Gross Alpha, Excl. Radon And U
3.01 pCi/L 20%
of the EPA limit 15 pCi/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 3.7 pCi/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Dibromoacetic Acid
2.329 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 2.366 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Bromoform
1.41 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
2/2 SYR4
Combined Radium (-226 And -228)
0.6501 pCi/L 13%
of the EPA limit 5 pCi/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
Highest in the ZIP: 1.0554 pCi/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Atrazine
0.0875 µg/L 2.9%
of the EPA limit 3 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2017
Highest in the ZIP: 0.3375 µg/L — LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
2/2 SYR4
Combined Uranium
0.1120 µg/L 0.4%
of the EPA limit 30 µg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2019
1/2 SYR4
Simazine
0.0800 µg/L 2%
of the EPA limit 4 µg/L
Highest in the ZIP: LOUDOUN WATER - CENTRAL SYSTEM · 334,808 people · 2019
1/2 SYR4
Pfpea
0.0215 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
2/2 UCMR-5
Pfba
0.0176 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
Pfhxa
0.0171 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
6:2 Fts
0.0101 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
PFBS
0.0081 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
PFOA
0.0074 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
PFOS
0.0057 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
Pfhpa
0.0056 µg/L
No EPA limit set
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2025
1/2 UCMR-5
Lead
0.0012 mg/L 8%
of the EPA limit 0.0150 mg/L
Main supplier: FAIRFAX COUNTY WATER AUTHORITY · 1,121,613 people · 2023
2/2 LCR
Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.

Water suppliers serving ZIP 20151

SupplierStatePopulation served
FAIRFAX COUNTY WATER AUTHORITY VA 1,121,613
LOUDOUN WATER - CENTRAL SYSTEM VA 334,808

Frequently asked questions about ZIP 20151 tap water

Is the tap water in ZIP 20151 safe to drink?

EPA testing detected 33 contaminants across the water suppliers serving ZIP 20151. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.

Which water suppliers serve ZIP 20151?

2 public water suppliers report EPA drinking-water monitoring for ZIP 20151. Each is listed above with its population served.

What contaminants are in ZIP 20151's water?

EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Copper, TTHM, and others across this ZIP's suppliers. The full list with levels and sources is above.