Tap WaterIndex

← Iowa

Tap water quality report

Knoxville, IA

EPA monitoring detected 18 contaminants across the 5 water suppliers serving Knoxville. 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.

5
water suppliers
14,790
people served
18
contaminants found
Iowa rankings Lead in Iowa PFAS in Iowa

What was found in Knoxville'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
Fluoride
1300 µg/L 33%
of the EPA limit 4000 µg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2013
1/5 SYR4
Nitrite
360 µg/L 36%
of the EPA limit 1000 µg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2019
1/5 SYR4
Copper
94.17 µg/L 7.2%
of the EPA limit 1300 µg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2019
Highest in the city: 267.1 µg/L — MARION CO. RURAL WATER DISTRICT · 5,687 people · 2018
3/5 SYR4
Lithium
150 µg/L
No EPA limit set
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2024
2/5 UCMR-5
Barium
16.1 µg/L 0.8%
of the EPA limit 2000 µg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2013
1/5 SYR4
TTHM
13.889 µg/L 17%
of the EPA limit 80 µg/L
Highest in the city: MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
1/5 SYR4
Lead
9.82 µg/L 65%
of the EPA limit 15 µg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2019
Highest in the city: 11.885 µg/L — MARION CO. RURAL WATER DISTRICT · 5,687 people · 2018
3/5 SYR4
Bromodichloromethane
6.18 µg/L
No EPA limit set
Highest in the city: MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
1/5 SYR4
Chloroform
4.208 µg/L
No EPA limit set
Highest in the city: MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
1/5 SYR4
Dibromochloromethane
3.4875 µg/L
No EPA limit set
Highest in the city: MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
1/5 SYR4
Combined Radium (-226 And -228)
3.108 pCi/L 62%
of the EPA limit 5 pCi/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2018
1/5 SYR4
Dichloroacetic Acid
1.89 µg/L
No EPA limit set
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2019
2/5 SYR4
Monochloroacetic Acid
1.67 µg/L
No EPA limit set
Highest in the city: MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
1/5 SYR4
Trichloroacetic Acid
0.7100 µg/L
No EPA limit set
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2019
Highest in the city: 1.0285 µg/L — MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
2/5 SYR4
Dibromoacetic Acid
0.6900 µg/L
No EPA limit set
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2019
Highest in the city: 0.9010 µg/L — MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
2/5 SYR4
Thallium, Total
0.6000 µg/L 30%
of the EPA limit 2 µg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2013
1/5 SYR4
Bromoform
0.5200 µg/L
No EPA limit set
Highest in the city: MARION CO. RURAL WATER DISTRICT · 5,687 people · 2019
1/5 SYR4
Lead
0.0078 mg/L 52%
of the EPA limit 0.0150 mg/L
Main supplier: KNOXVILLE WATER WORKS · 8,400 people · 2025
5/5 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 Knoxville

SupplierPopulation served
KNOXVILLE WATER WORKS 8,400
MARION CO. RURAL WATER DISTRICT 5,687
WHEEL ESTATES MHC 315
COLONIAL TERRACE MHP LLC 250
SOUTHSHORE HEIGHTS 138

Frequently asked questions about Knoxville tap water

Is Knoxville tap water safe to drink?

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

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

What contaminants are in Knoxville's water?

The contaminants EPA monitoring detected in Knoxville include Fluoride, Nitrite, Copper, Lithium, Barium. 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.