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Tap water quality report

Grass Valley, CA

EPA monitoring detected 15 contaminants across the 6 water suppliers serving Grass Valley. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

6
water suppliers
52,186
people served
15
contaminants found
California rankings Lead in California PFAS in California

What was found in Grass Valley's water

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

ContaminantLevel vs EPA limitSuppliersSource
Nitrate-Nitrite
475042 µg/L 4750%
of the EPA limit, at the 95th percentile of samples — 10000 µg/L
Highest in the city: CHRISTIAN ENCOUNTER MINISTRIES · 35 people · 2017
1/6 SYR4
Nitrate
980.84 µg/L 9.8%
of the EPA limit 10000 µg/L
Highest in the city: CHRISTIAN ENCOUNTER MINISTRIES · 35 people · 2019
1/6 SYR4
TTHM
45 µg/L 56%
of the EPA limit 80 µg/L
Main supplier: NEVADA ID - E. GEORGE, BANNER MOUNTAIN · 17,154 people · 2019
Highest in the city: 62.3 µg/L — NEVADA ID - LOMA RICA · 14,072 people · 2019
5/6 SYR4
Chloroform
44 µg/L
No EPA limit set
Main supplier: NEVADA ID - E. GEORGE, BANNER MOUNTAIN · 17,154 people · 2019
Highest in the city: 60.3 µg/L — NEVADA ID - LOMA RICA · 14,072 people · 2019
5/6 SYR4
Total Haloacetic Acids (HAA5)
27.2 µg/L 45%
of the EPA limit 60 µg/L
Highest in the city: NEVADA ID - LOMA RICA · 14,072 people · 2018
2/6 SYR4
Trichloroacetic Acid
20.2 µg/L
No EPA limit set
Highest in the city: NEVADA ID - LOMA RICA · 14,072 people · 2018
2/6 SYR4
Dichloroacetic Acid
10 µg/L
No EPA limit set
Highest in the city: NEVADA ID - LOMA RICA · 14,072 people · 2018
2/6 SYR4
Selenium
7.4 µg/L 15%
of the EPA limit 50 µg/L
Highest in the city: CITY OF GRASS VALLEY · 4,947 people · 2019
1/6 SYR4
Arsenic
6.6 µg/L 66%
of the EPA limit 10 µg/L
Main supplier: NEVADA ID - E. GEORGE, BANNER MOUNTAIN · 17,154 people · 2019
2/6 SYR4
Bromodichloromethane
1.1 µg/L
No EPA limit set
Main supplier: NEVADA ID - E. GEORGE, BANNER MOUNTAIN · 17,154 people · 2019
Highest in the city: 2.54 µg/L — NEVADA ID - LAKE WILDWOOD · 9,108 people · 2019
5/6 SYR4
Copper
2.47 µg/L 0.2%
of the EPA limit 1300 µg/L
Highest in the city: CHRISTIAN ENCOUNTER MINISTRIES · 35 people · 2018
1/6 SYR4
Barium
2.11 µg/L 0.1%
of the EPA limit 2000 µg/L
Highest in the city: CHRISTIAN ENCOUNTER MINISTRIES · 35 people · 2017
1/6 SYR4
Styrene
1.29 µg/L 1.3%
of the EPA limit 100 µg/L
Main supplier: NEVADA ID - E. GEORGE, BANNER MOUNTAIN · 17,154 people · 2019
Highest in the city: 1.6 µg/L — NEVADA ID - LOMA RICA · 14,072 people · 2019
3/6 SYR4
Combined Uranium
0.1341 µg/L 0.4%
of the EPA limit 30 µg/L
Highest in the city: CHRISTIAN ENCOUNTER MINISTRIES · 35 people · 2016
1/6 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: NEVADA ID - E. GEORGE, BANNER MOUNTAIN · 17,154 people · 2024
Highest in the city: 0.0045 mg/L — CHRISTIAN ENCOUNTER MINISTRIES · 35 people · 2023
6/6 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. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Grass Valley

SupplierPopulation served
NEVADA ID - E. GEORGE, BANNER MOUNTAIN 17,154
NEVADA ID - LOMA RICA 14,072
NEVADA ID - LAKE WILDWOOD 9,108
NEVADA ID - LAKE OF PINES 6,870
CITY OF GRASS VALLEY 4,947
CHRISTIAN ENCOUNTER MINISTRIES 35

Frequently asked questions about Grass Valley tap water

Is Grass Valley tap water safe to drink?

EPA testing detected 15 contaminants in the water serving Grass Valley. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Grass Valley?

6 public water suppliers report drinking-water monitoring for Grass Valley, California to the EPA. Each is listed above with its population served.

What contaminants are in Grass Valley's water?

The contaminants EPA monitoring detected in Grass Valley include Nitrate-Nitrite, Nitrate, TTHM, Chloroform, Total Haloacetic Acids (HAA5). The full list, with the level at the main supplier and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.