Is Caldwell, ID Tap Water Safe? Quality & Contaminants

What was found in Caldwell'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	2100 µg/L 21% of the EPA limit 10000 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 14300 µg/L — GEM STATE ACADEMY · 121 people · 2019	21/22	SYR4
Nitrate-Nitrite	2150 µg/L 22% of the EPA limit 10000 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 13705 µg/L — GEM STATE ACADEMY · 121 people · 2014	16/22	SYR4
Fluoride	770 µg/L 19% of the EPA limit 4000 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 968.6 µg/L — EAST LIZARD BUTTE WATER CORP · 95 people · 2019	19/22	SYR4
Barium	60 µg/L 3% of the EPA limit 2000 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 170 µg/L — IDAHO YOUTH RANCH HANDS OF PROMISE · 95 people · 2019	13/22	SYR4
Toluene	41.8 µg/L 4.2% of the EPA limit 1000 µg/L Highest in the city: RICH SUBD · 60 people · 2019	2/22	SYR4
Combined Uranium	12.2 µg/L 41% of the EPA limit 30 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 32.9 µg/L — CALDWELL HOUSING AUTHORITY · 1,100 people · 2019	19/22	SYR4
Arsenic	8 µg/L 80% of the EPA limit 10 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 25.6 µg/L — MAVERICK SUBD LASHER CONSTRUCTION · 90 people · 2019	20/22	SYR4
Lithium	16 µg/L No EPA limit set Main supplier: CALDWELL CITY OF · 74,000 people · 2025	1/22	UCMR-5
TTHM	15.46 µg/L 19% of the EPA limit 80 µg/L Highest in the city: CALDWELL HOUSING AUTHORITY · 1,100 people · 2019	2/22	SYR4
Gross Alpha, Excl. Radon And U	11.595 pCi/L 77% of the EPA limit 15 pCi/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 12.515 pCi/L — CALDWELL HOUSING AUTHORITY · 1,100 people · 2019	9/22	SYR4
Chromium	5 µg/L 5% of the EPA limit 100 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 8 µg/L — OWYHEE VILLAGE SUBD WATER ASSN INC · 200 people · 2013	9/22	SYR4
Gross Beta Particle Activity	7.8 pCi/L No EPA limit set Highest in the city: STECHER WATER USERS ASSN · 70 people · 2015	2/22	SYR4
Total Haloacetic Acids (HAA5)	2.08 µg/L 3.5% of the EPA limit 60 µg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019 Highest in the city: 6.63 µg/L — CALDWELL HOUSING AUTHORITY · 1,100 people · 2019	3/22	SYR4
Tetrachloroethylene	2.24 µg/L 45% of the EPA limit 5 µg/L Highest in the city: GEM STATE ACADEMY · 121 people · 2019	1/22	SYR4
Selenium	2 µg/L 4% of the EPA limit 50 µg/L Highest in the city: IDAHO YOUTH RANCH HANDS OF PROMISE · 95 people · 2019	1/22	SYR4
Combined Radium (-226 And -228)	1.8 pCi/L 36% of the EPA limit 5 pCi/L Main supplier: CALDWELL CITY OF · 74,000 people · 2019	7/22	SYR4
Di(2-ethylhexyl) Phthalate	1.04 µg/L 17% of the EPA limit 6 µg/L Highest in the city: KARCHER RANCHETTE WATER CORP · 213 people · 2019	2/22	SYR4
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CALDWELL CITY OF · 74,000 people · 2023 Highest in the city: 0.0090 mg/L — CALDWELL HOUSING AUTHORITY · 1,100 people · 2026	22/22	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 Caldwell

Supplier	Population served
CALDWELL CITY OF	74,000
CALDWELL HOUSING AUTHORITY	1,100
EL RANCHO HEIGHTS	300
WOODVIEW ACRES PROPERTY OWNERS	245
KARCHER RANCHETTE WATER CORP	213
SOMERSET WEST WATER CORP	203
OWYHEE VILLAGE SUBD WATER ASSN INC	200
DRAKE SUBD	150
RIO VISTA WATER COMPANY 3	140
PAR ESTATES HOMEOWNERS ASSN	140
GEM STATE ACADEMY	121
COUNTRY CLUB SUBDIVISIONS WATER ASSN	120
PLEASANT VIEW MANOR	100
IDAHO YOUTH RANCH HANDS OF PROMISE	95
EAST LIZARD BUTTE WATER CORP	95
MAVERICK SUBD LASHER CONSTRUCTION	90
STECHER WATER USERS ASSN	70
STECHER MUTUAL WATER COMPANY	62
RICH SUBD	60
VANAL HEIGHTS WELL ASSN	48
VANAL HEIGHTS SWEET WATER	45
WILDROSE ESTATES	40

Frequently asked questions about Caldwell tap water

Is Caldwell tap water safe to drink?

EPA testing detected 18 contaminants in the water serving Caldwell. 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 Caldwell?

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

What contaminants are in Caldwell's water?

The contaminants EPA monitoring detected in Caldwell include Nitrate, Nitrate-Nitrite, Fluoride, Barium, Toluene. 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.