Is Nampa, ID Tap Water Safe? Quality & Contaminants

What was found in Nampa'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.

Contaminant	Level vs EPA limit	Suppliers	Source
Nitrate	6185 µg/L 62% of the EPA limit 10000 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 9260 µg/L — SUNNYRIDGE I SUBD · 35 people · 2019	37/41	SYR4
Nitrate-Nitrite	5825 µg/L 58% of the EPA limit 10000 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 6400 µg/L — LOCUST SUBD · 42 people · 2019	31/41	SYR4
Fluoride	1460.5 µg/L 37% of the EPA limit 4000 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 2389.5 µg/L — SKY RANCH ESTATES · 104 people · 2019	38/41	SYR4
Barium	100 µg/L 5% of the EPA limit 2000 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 140 µg/L — SUNNYRIDGE I SUBD · 35 people · 2019	28/41	SYR4
Lithium	42.1 µg/L No EPA limit set Main supplier: NAMPA CITY OF · 100,200 people · 2025	1/41	UCMR-5
Arsenic	7.4 µg/L 74% of the EPA limit 10 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 29.25 µg/L — VALLEY VIEW WATER · 57 people · 2019	35/41	SYR4
Combined Uranium	18.4 µg/L 61% of the EPA limit 30 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2018 Highest in the city: 27.3 µg/L — M AND M MOUNTAIN VIEW SUBD EM2 · 54 people · 2018	36/41	SYR4
Gross Alpha, Excl. Radon And U	17.202 pCi/L 115% of the EPA limit, at the 95th percentile of samples — 15 pCi/L Main supplier: NAMPA CITY OF · 100,200 people · 2018	15/41	SYR4
Nitrite	10 µg/L 1% of the EPA limit 1000 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019	1/41	SYR4
Chromium	5.6 µg/L 5.6% of the EPA limit 100 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 7.95 µg/L — VERDE HILLS WATER USERS ASSN INC · 95 people · 2015	20/41	SYR4
TTHM	7.87 µg/L 9.8% of the EPA limit 80 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019	2/41	SYR4
Total Haloacetic Acids (HAA5)	5.857 µg/L 9.8% of the EPA limit 60 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019	2/41	SYR4
Combined Radium (-226 And -228)	2.077 pCi/L 42% of the EPA limit 5 pCi/L Main supplier: NAMPA CITY OF · 100,200 people · 2019 Highest in the city: 2.6275 pCi/L — M AND M MOUNTAIN VIEW SUBD EM2 · 54 people · 2018	18/41	SYR4
Di(2-ethylhexyl) Phthalate	1.43 µg/L 24% of the EPA limit 6 µg/L Main supplier: NAMPA CITY OF · 100,200 people · 2019	2/41	SYR4
2,4-D	0.8610 µg/L 1.2% of the EPA limit 70 µg/L Highest in the city: SOUTHSHORE WATER · 60 people · 2019	1/41	SYR4
Lead	0.0020 mg/L 13% of the EPA limit 0.0150 mg/L Main supplier: NAMPA CITY OF · 100,200 people · 2024 Highest in the city: 0.0070 mg/L — M AND M MOUNTAIN VIEW SUBD EM2 · 54 people · 2023	40/41	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 Nampa

Supplier	Population served
NAMPA CITY OF	100,200
SHALIMAR SUBD	370
BELLE AIRE ACRES 2	350
EVERGREEN MOBILE PARK	284
ROLLING HILLS ESTATES WATER COMPANY	250
COVERT WATER USERS ASSOCIATION	250
SUNNYRIDGE 3 WATER CORP	240
INDIAN VILLAGE	225
LAKEVIEW HILLS WATER USERS ASSOCIATION	160
CAMELOT WATER ASSN INC	157
CLARK THEURER WATER ASSN	155
LEISURE HEIGHTS HOMEOWNERS ASSOCIATION	142
OK WATER ASSN	140
SHAMROCK VILLA WATER ASSN	130
APACHE HEIGHTS SUBDIVISION (2)	110
SKY RANCH ESTATES	104
M & T WATER CORP	100
NORTHSIDE ESTATES HOA INC	100
KARCHER ACRES SUBD	100
VERDE HILLS WATER USERS ASSN INC	95
WESTVIEW SHERVIK SUBD	78
MANGUM HEIGHTS SUBD	75
HORIZON RIDGE SUBDIVISION	75
SOUTHSHORE WATER	60
VALLEY VIEW WATER	57
BURNIE SUBD	55
M AND M MOUNTAIN VIEW SUBD EM2	54
SUNNYRIDGE PROPERTY OWNERS	53
DAHL SUBD	51
SKYLINE WATER ASSN	50
LAKERIDGE SECOND SUBD	50
NORTHSTAR SUBDIVISION	50
LINDENWOOD WATER ASSN	48
SILVER SPUR SUBDIVISION	44
LOCUST SUBD	42
SHIPMAN PLACE SUBD	40
COUNTRY MEADOWS SUBD	35
SUNNYRIDGE I SUBD	35
SUNNYRIDGE SUBD 2	34
AURORA SUBD	30
TWIN BRIDGES SUBD	28

Frequently asked questions about Nampa tap water

Is Nampa tap water safe to drink?

EPA testing detected 16 contaminants in the water serving Nampa. 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 Nampa?

41 public water suppliers report drinking-water monitoring for Nampa, Idaho to the EPA. Each is listed above with its population served.

What contaminants are in Nampa's water?

The contaminants EPA monitoring detected in Nampa include Nitrate, Nitrate-Nitrite, Fluoride, Barium, Lithium. 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.