Is Delavan Waterworks Tap Water Safe? Quality Report

Water source: Ground water
Ownership: Local government
Counties served: Walworth

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

violations on file

still open

Violation	Type	Status	Period
MON	Monitoring	Archived	2026-01-01 → 2026-01-31
MON	Monitoring	Archived	2026-01-01 → 2026-01-31
MR	Monitoring	Resolved	2017-01-01 → 2017-12-31
MR	Monitoring	Resolved	2017-01-01 → 2017-12-31
MR	Monitoring	Resolved	2017-01-01 → 2017-12-31
MR	Monitoring	Resolved	2017-01-01 → 2017-12-31
MR	Monitoring	Resolved	2003-01-01 → 2003-01-31
MR	Monitoring	Resolved	2002-12-01 → 2002-12-31
MR	Monitoring	Resolved	2002-11-01 → 2002-11-30
MR	Monitoring	Resolved	2002-10-01 → 2002-10-31

Other contaminants detected

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 this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
Fluoride	993.2 µg/L 25% of the EPA limit 4000 µg/L worst single sample: 1600 µg/L	103/200	SYR4	2012–2019
Copper	1005 µg/L 77% of the EPA limit 1300 µg/L worst single sample: 2200 µg/L	40/40	SYR4	2014–2017
Lead	11.15 µg/L 74% of the EPA limit 15 µg/L worst single sample: 110 µg/L	40/40	SYR4	2014–2017
Nitrate	1100 µg/L 11% of the EPA limit 10000 µg/L	22/36	SYR4	2012–2019
Combined Radium (-226 And -228)	6.949 pCi/L 139% of the EPA limit, at the 95th percentile of samples — 5 pCi/L worst single sample: 7.88 pCi/L	20/20	SYR4	2012–2019
Lead	0.0100 mg/L 67% of the EPA limit 0.0150 mg/L	15/15	LCR	2023
Chloroform	1.72 µg/L No EPA limit set worst single sample: 2.5 µg/L	14/44	SYR4	2012–2019
Gross Alpha, Excl. Radon And U	2.97 pCi/L 20% of the EPA limit 15 pCi/L worst single sample: 3.21 pCi/L	9/9	SYR4	2015–2019
TTHM	2.828 µg/L 3.5% of the EPA limit 80 µg/L worst single sample: 3.58 µg/L	9/9	SYR4	2013–2019
Combined Uranium	2.3495 µg/L 7.8% of the EPA limit 30 µg/L worst single sample: 2.36 µg/L	8/8	SYR4	2017–2019
Total Haloacetic Acids (HAA5)	0.6870 µg/L 1.1% of the EPA limit 60 µg/L worst single sample: 0.6900 µg/L	7/9	SYR4	2013–2019
Barium	335 µg/L 17% of the EPA limit 2000 µg/L worst single sample: 340 µg/L	6/6	SYR4	2014–2017
Bromodichloromethane	0.8880 µg/L No EPA limit set worst single sample: 0.9000 µg/L	4/31	SYR4	2013–2019
Nitrate-Nitrite	797.5 µg/L 8% of the EPA limit 10000 µg/L worst single sample: 820 µg/L	4/6	SYR4	2014–2017
Dibromochloromethane	2.65 µg/L No EPA limit set worst single sample: 2.8 µg/L	3/19	SYR4	2013–2019
Dichloroacetic Acid	0.3190 µg/L No EPA limit set worst single sample: 0.3200 µg/L	2/9	SYR4	2013–2019
Bromoform	3.7 µg/L No EPA limit set	1/13	SYR4	2013–2019
Nitrite	280 µg/L 28% of the EPA limit 1000 µg/L	1/6	SYR4	2014–2017
Trichloroacetic Acid	0.3800 µg/L No EPA limit set	1/9	SYR4	2013–2019

58 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAntimony, TotalArsenicAtrazineBhc-GammaBenzeneBeryllium, TotalChlorobenzeneCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDibromoacetic AcidDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidMonochloroacetic AcidOxamylPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

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Frequently asked questions about Delavan Waterworks

Is Delavan Waterworks tap water safe to drink?

EPA monitoring detected 19 contaminants in Delavan Waterworks's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Delavan Waterworks's water?

EPA monitoring detected Fluoride, Copper, Lead, Nitrate, Combined Radium (-226 And -228), and others. The full list with the level and data source for each is above.

How many people does Delavan Waterworks serve?

Delavan Waterworks reports serving 9,028 people in Wisconsin, per its EPA record.

Has Delavan Waterworks had any water quality violations?

The EPA has 84 violations on file for Delavan Waterworks, of which 0 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

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.