Is Delaware, OH Tap Water Safe? Quality & Contaminants

What was found in Delaware'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
Nitrate	5200 µg/L 52% of the EPA limit 10000 µg/L	2/2	SYR4
Nitrate-Nitrite	5200 µg/L 52% of the EPA limit 10000 µg/L	2/2	SYR4
Copper	2000 µg/L 154% of the EPA limit, in the worst sample — 1300 µg/L	2/2	SYR4
Fluoride	1430 µg/L 36% of the EPA limit 4000 µg/L	2/2	SYR4
Nitrite	180 µg/L 18% of the EPA limit 1000 µg/L	1/2	SYR4
TTHM	127.6 µg/L 160% of the EPA limit, in the worst sample — 80 µg/L	2/2	SYR4
Chloroform	105.5 µg/L No EPA limit set	2/2	SYR4
Barium	68 µg/L 3.4% of the EPA limit 2000 µg/L	2/2	SYR4
Total Haloacetic Acids (HAA5)	58 µg/L 97% of the EPA limit 60 µg/L	2/2	SYR4
Lead	35 µg/L 233% of the EPA limit, in the worst sample — 15 µg/L	2/2	SYR4
Dichloroacetic Acid	33 µg/L No EPA limit set	2/2	SYR4
Monochloroacetic Acid	32.5 µg/L No EPA limit set	2/2	SYR4
Trichloroacetic Acid	27.1 µg/L No EPA limit set	2/2	SYR4
Gross Beta Particle Activity	25 pCi/L No EPA limit set	1/2	SYR4
Bromodichloromethane	21.8 µg/L No EPA limit set	2/2	SYR4
Lithium	15.4 µg/L No EPA limit set	2/2	UCMR-5
Dibromochloromethane	7.1 µg/L No EPA limit set	2/2	SYR4
Atrazine	6.7 µg/L 223% of the EPA limit, in the worst sample — 3 µg/L	2/2	SYR4
Arsenic	3.1 µg/L 31% of the EPA limit 10 µg/L	1/2	SYR4
Dibromoacetic Acid	2.4 µg/L No EPA limit set	2/2	SYR4
Monobromoacetic Acid	2.1 µg/L No EPA limit set	1/2	SYR4
Xylenes, Total	1.5 µg/L 0% of the EPA limit 10000 µg/L	2/2	SYR4
Simazine	1.2 µg/L 30% of the EPA limit 4 µg/L	2/2	SYR4
Toluene	1.2 µg/L 0.1% of the EPA limit 1000 µg/L	2/2	SYR4
Bromoform	0.6000 µg/L No EPA limit set	2/2	SYR4
Lasso	0.6000 µg/L 30% of the EPA limit 2 µg/L	1/2	SYR4
Pfba	0.0107 µg/L No EPA limit set	1/2	UCMR-5
Pfhxa	0.0087 µg/L No EPA limit set	1/2	UCMR-5
Pfpea	0.0063 µg/L No EPA limit set	1/2	UCMR-5
PFBS	0.0043 µg/L No EPA limit set	1/2	UCMR-5
PFOA	0.0042 µg/L No EPA limit set	1/2	UCMR-5
Lead	0.00082 mg/L 5.5% 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 Delaware

Supplier	Population served
DEL-CO WATER COMPANY, INC.	150,000
DELAWARE CITY PWS	43,895

Frequently asked questions about Delaware tap water

Is Delaware tap water safe to drink?

EPA testing detected 32 contaminants in the water serving Delaware. 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 Delaware?

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

What contaminants are in Delaware's water?

The contaminants EPA monitoring detected in Delaware include Nitrate, Nitrate-Nitrite, Copper, Fluoride, Nitrite. 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.