Is Sister Bay Waterworks Tap Water Safe? Quality Report

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

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
Other	Monitoring	Resolved	2015-07-01
Other	Monitoring	Resolved	2015-07-01
Other	Monitoring	Resolved	2001-07-01
MR	Monitoring	Resolved	1995-05-01 → 1995-05-31
MR	Monitoring	Resolved	1995-05-01 → 1995-05-31
MR	Monitoring	Resolved	1995-05-01 → 1995-05-31
MR	Monitoring	Resolved	1995-05-01 → 1995-05-31

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
Nitrate	2800 µg/L 28% of the EPA limit 10000 µg/L worst single sample: 3100 µg/L	36/36	SYR4	2012–2019
Copper	761.5 µg/L 59% of the EPA limit 1300 µg/L worst single sample: 790 µg/L	20/20	SYR4	2014–2017
Lead	9.715 µg/L 65% of the EPA limit 15 µg/L worst single sample: 10 µg/L	20/20	SYR4	2014–2017
Lead	0.0061 mg/L 41% of the EPA limit 0.0150 mg/L	14/14	LCR	2023
Bromodichloromethane	3.475 µg/L No EPA limit set worst single sample: 3.7 µg/L	10/10	SYR4	2013–2019
Chloroform	2.9 µg/L No EPA limit set worst single sample: 3.1 µg/L	9/10	SYR4	2013–2019
TTHM	13.48 µg/L 17% of the EPA limit 80 µg/L worst single sample: 14 µg/L	9/9	SYR4	2013–2019
Total Haloacetic Acids (HAA5)	2.526 µg/L 4.2% of the EPA limit 60 µg/L worst single sample: 2.63 µg/L	9/9	SYR4	2013–2019
Dibromochloromethane	4.93 µg/L No EPA limit set worst single sample: 5 µg/L	8/10	SYR4	2013–2019
Barium	63.25 µg/L 3.2% of the EPA limit 2000 µg/L worst single sample: 64 µg/L	6/6	SYR4	2014–2017
Fluoride	540 µg/L 14% of the EPA limit 4000 µg/L	6/6	SYR4	2014–2017
Nitrate-Nitrite	2050 µg/L 21% of the EPA limit 10000 µg/L worst single sample: 2100 µg/L	6/6	SYR4	2014–2017
Dibromoacetic Acid	1.28 µg/L No EPA limit set worst single sample: 1.3 µg/L	5/9	SYR4	2013–2019
Bromoform	4.26 µg/L No EPA limit set worst single sample: 4.5 µg/L	4/9	SYR4	2013–2019
Combined Radium (-226 And -228)	3.643 pCi/L 73% of the EPA limit 5 pCi/L worst single sample: 4.03 pCi/L	4/4	SYR4	2014–2017
Dichloroacetic Acid	0.9270 µg/L No EPA limit set worst single sample: 0.9600 µg/L	4/9	SYR4	2013–2019
Trichloroacetic Acid	0.6195 µg/L No EPA limit set worst single sample: 0.6300 µg/L	4/9	SYR4	2013–2019
Gross Alpha, Excl. Radon And U	3.95183 pCi/L 26% of the EPA limit 15 pCi/L worst single sample: 4.03 pCi/L	2/2	SYR4	2014–2017
Tetrachloroethylene	2.16 µg/L 43% of the EPA limit 5 µg/L worst single sample: 2.2 µg/L	2/9	SYR4	2013–2018
Combined Uranium	1.16 µg/L 3.9% of the EPA limit 30 µg/L	1/1	SYR4	2017
Monobromoacetic Acid	0.4800 µg/L No EPA limit set	1/9	SYR4	2013–2019

54 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, TotalArsenicAtrazineBhc-GammaBenzeneBeryllium, TotalChlorobenzeneCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDinosebDiquatEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonochloroacetic AcidNitriteOxamylPentachlorophenolPicloramSeleniumSimazineStyreneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

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Frequently asked questions about Sister Bay Waterworks

Is Sister Bay Waterworks tap water safe to drink?

EPA monitoring detected 21 contaminants in Sister 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 Sister Bay Waterworks's water?

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

How many people does Sister Bay Waterworks serve?

Sister Bay Waterworks reports serving 1,000 people in Wisconsin, per its EPA record.

Has Sister Bay Waterworks had any water quality violations?

The EPA has 7 violations on file for Sister Bay 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.