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Tap water quality report

Williams Bay Waterworks

EPA monitoring tested this supplier for 73 contaminants and detected 17. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

73
contaminants tested
17
detected
2,601
people served
4
health-based violations
Wisconsin rankingsLead in WisconsinPFAS in Wisconsin
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.

4
health-based violations
138
violations on file
4
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2025-07-01
TT Health-based Resolved 2025-07-01
TT Health-based Resolved 2025-07-01
TT Health-based Resolved 2025-07-01
Other Monitoring Resolved 2025-09-11
MR Monitoring Unaddressed 2025-01-01
MR Monitoring Unaddressed 2025-01-01
MR Monitoring Unaddressed 2025-01-01
MR Monitoring Unaddressed 2025-01-01
MR Monitoring Archived 2025-01-01 → 2025-06-30

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.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Fluoride
1220 µg/L 31%
of the EPA limit 4000 µg/L
worst single sample: 1290 µg/L
94/186 SYR4 2012–2019
Nitrate
230 µg/L 2.3%
of the EPA limit 10000 µg/L
worst single sample: 270 µg/L
56/62 SYR4 2012–2019
Lead
11 µg/L 73%
of the EPA limit 15 µg/L
worst single sample: 15 µg/L
51/51 SYR4 2014–2019
Copper
1750 µg/L 135%
of the EPA limit, at the 95th percentile of samples — 1300 µg/L
worst single sample: 2700 µg/L
50/51 SYR4 2014–2019
Nitrite
169 µg/L 17%
of the EPA limit 1000 µg/L
worst single sample: 250 µg/L
22/32 SYR4 2012–2019
Lead
0.0160 mg/L 107%
above the EPA limit of 0.0150 mg/L
 18/18 LCR 2025
Chloroform
2.1 µg/L
No EPA limit set
 7/9 SYR4 2013–2019
TTHM
2.1 µg/L 2.6%
of the EPA limit 80 µg/L
 7/7 SYR4 2013–2019
Total Haloacetic Acids (HAA5)
5.487 µg/L 9.1%
of the EPA limit 60 µg/L
worst single sample: 6.15 µg/L
7/7 SYR4 2013–2019
Dichloroacetic Acid
5.015 µg/L
No EPA limit set
worst single sample: 5.3 µg/L
4/7 SYR4 2013–2019
Nitrate-Nitrite
257 µg/L 2.6%
of the EPA limit 10000 µg/L
worst single sample: 260 µg/L
3/3 SYR4 2012–2017
Trichloroacetic Acid
0.6930 µg/L
No EPA limit set
worst single sample: 0.7100 µg/L
3/7 SYR4 2013–2019
Arsenic
2.82 µg/L 28%
of the EPA limit 10 µg/L
worst single sample: 2.9 µg/L
2/2 SYR4 2014–2017
Barium
16.9 µg/L 0.8%
of the EPA limit 2000 µg/L
worst single sample: 17 µg/L
2/2 SYR4 2014–2017
Combined Radium (-226 And -228)
1.2 pCi/L 24%
of the EPA limit 5 pCi/L
 1/1 SYR4 2014
Dibromoacetic Acid
1.1 µg/L
No EPA limit set
 1/7 SYR4 2013–2019
Monochloroacetic Acid
2 µg/L
No EPA limit set
 1/7 SYR4 2013–2019
56 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAntimony, TotalAtrazineBhc-GammaBenzeneBeryllium, TotalBromodichloromethaneBromoformChlorobenzeneCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDibromochloromethaneDinosebDiquatEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidOxamylPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Frequently asked questions about Williams Bay Waterworks

Is Williams Bay Waterworks tap water safe to drink?

EPA monitoring detected 17 contaminants in Williams Bay 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 Williams Bay Waterworks's water?

EPA monitoring detected Fluoride, Nitrate, Lead, Copper, Nitrite, and others. The full list with the level and data source for each is above.

How many people does Williams Bay Waterworks serve?

Williams Bay Waterworks reports serving 2,601 people in Wisconsin, per its EPA record.

Has Williams Bay Waterworks had any water quality violations?

The EPA has 138 violations on file for Williams Bay Waterworks, of which 4 are health-based (a contaminant limit or required treatment was breached) and 4 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.