Is Sioux City, IA Tap Water Safe? Quality & Contaminants

What was found in Sioux City's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

Contaminant	Level vs EPA limit	Suppliers	Source
Copper	3800 µg/L 292% of the EPA limit, in the worst sample — 1300 µg/L	1/2	SYR4
Nitrate	2600 µg/L 26% of the EPA limit 10000 µg/L	1/2	SYR4
Fluoride	660 µg/L 17% of the EPA limit 4000 µg/L	1/2	SYR4
Lithium	240 µg/L No EPA limit set	1/2	UCMR-5
Lead	230 µg/L 1533% of the EPA limit, in the worst sample — 15 µg/L	1/2	SYR4
TTHM	140 µg/L 175% of the EPA limit, in the worst sample — 80 µg/L	1/2	SYR4
Chloroform	90 µg/L No EPA limit set	1/2	SYR4
Total Haloacetic Acids (HAA5)	59 µg/L 98% of the EPA limit 60 µg/L	1/2	SYR4
Bromodichloromethane	35 µg/L No EPA limit set	1/2	SYR4
Trichloroacetic Acid	31 µg/L No EPA limit set	1/2	SYR4
Dichloroacetic Acid	29 µg/L No EPA limit set	1/2	SYR4
Dibromochloromethane	16 µg/L No EPA limit set	1/2	SYR4
Dibromoacetic Acid	3 µg/L No EPA limit set	1/2	SYR4
Monochloroacetic Acid	3 µg/L No EPA limit set	1/2	SYR4
Toluene	2.5 µg/L 0.3% of the EPA limit 1000 µg/L	1/2	SYR4
Bromoform	2.3 µg/L No EPA limit set	1/2	SYR4
Arsenic	2 µg/L 20% of the EPA limit 10 µg/L	1/2	SYR4
Carbon Tetrachloride	1 µg/L 20% of the EPA limit 5 µg/L	1/2	SYR4
cis-1,2-Dichloroethylene	0.9000 µg/L 1.3% of the EPA limit 70 µg/L	1/2	SYR4
PFHXS	0.0350 µg/L No EPA limit set	1/2	UCMR-5
Pfhxa	0.0330 µg/L No EPA limit set	1/2	UCMR-5
Pfpea	0.0220 µg/L No EPA limit set	1/2	UCMR-5
PFBS	0.0210 µg/L No EPA limit set	1/2	UCMR-5
Pfpes	0.0140 µg/L No EPA limit set	1/2	UCMR-5
Pfba	0.0092 µg/L No EPA limit set	1/2	UCMR-5
PFOA	0.0060 µg/L No EPA limit set	1/2	UCMR-5
Pfhpa	0.0048 µg/L No EPA limit set	1/2	UCMR-5
PFOS	0.0043 µg/L No EPA limit set	1/2	UCMR-5
Lead	0.0020 mg/L 13% of the EPA limit 0.0150 mg/L	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 single worst sample on record — 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 Sioux City

Supplier	Population served
SIOUX CITY WATER SUPPLY	85,791
BEREA HEIGHTS INC	33

Frequently asked questions about Sioux City tap water

Is Sioux City tap water safe to drink?

EPA testing detected 29 contaminants in the water serving Sioux City. 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 Sioux City?

2 public water suppliers report drinking-water monitoring for Sioux City, Iowa to the EPA. Each is listed above with its population served.

What contaminants are in Sioux City's water?

The contaminants EPA monitoring detected in Sioux City include Copper, Nitrate, Fluoride, Lithium, Lead. The full list, with the highest level found 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.