Tap WaterIndex

← Illinois

Tap water quality report

Decatur, IL

EPA monitoring detected 22 contaminants across the 2 water suppliers serving Decatur. 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.

2
water suppliers
76,622
people served
22
contaminants found
Illinois rankings Lead in Illinois PFAS in Illinois

What was found in Decatur'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
7900 µg/L 79%
of the EPA limit 10000 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Nitrate-Nitrite
6619 µg/L 66%
of the EPA limit 10000 µg/L
Main supplier: DECATUR · 76,122 people · 2018
1/2 SYR4
Fluoride
1133.5 µg/L 28%
of the EPA limit 4000 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Chlorite
482.5 µg/L 48%
of the EPA limit 1000 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
TTHM
76.725 µg/L 96%
of the EPA limit 80 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Chloroform
60.844 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Copper
45.975 µg/L 3.5%
of the EPA limit 1300 µg/L
Main supplier: DECATUR · 76,122 people · 2017
1/2 SYR4
Barium
20.4 µg/L 1%
of the EPA limit 2000 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Total Haloacetic Acids (HAA5)
19.91 µg/L 33%
of the EPA limit 60 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Dichloroacetic Acid
15.3 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Bromodichloromethane
13.1715 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Lead
7.2 µg/L 48%
of the EPA limit 15 µg/L
Main supplier: DECATUR · 76,122 people · 2017
1/2 SYR4
Selenium
6.5 µg/L 13%
of the EPA limit 50 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Dibromochloromethane
5.996 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Trichloroacetic Acid
5.8155 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Monobromoacetic Acid
4.527 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Monochloroacetic Acid
4.2275 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Dibromoacetic Acid
2.155 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Bromoform
1.88468 µg/L
No EPA limit set
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Arsenic
1.58 µg/L 16%
of the EPA limit 10 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Atrazine
0.4000 µg/L 13%
of the EPA limit 3 µg/L
Main supplier: DECATUR · 76,122 people · 2019
1/2 SYR4
Lead
0.0026 mg/L 17%
of the EPA limit 0.0150 mg/L
Main supplier: DECATUR · 76,122 people · 2025
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 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 Decatur

SupplierPopulation served
DECATUR 76,122
DECATUR MHP, LLC 500

Frequently asked questions about Decatur tap water

Is Decatur tap water safe to drink?

EPA testing detected 22 contaminants in the water serving Decatur. 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 Decatur?

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

What contaminants are in Decatur's water?

The contaminants EPA monitoring detected in Decatur include Nitrate, Nitrate-Nitrite, Fluoride, Chlorite, TTHM. 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.