Is Mt Horeb Waterworks Tap Water Safe? Quality Report

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

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

180

violations on file

still open

Violation	Type	Status	Period
TT	Health-based	Resolved	2011-01-01
Other	Monitoring	Unaddressed	2011-10-01
MR	Monitoring	Resolved	2005-01-01 → 2005-03-31
MR	Monitoring	Resolved	2005-01-01 → 2005-03-31
MR	Monitoring	Resolved	2005-01-01 → 2005-03-31
MR	Monitoring	Resolved	2005-01-01 → 2005-03-31
MR	Monitoring	Resolved	2005-01-01 → 2005-03-31
MR	Monitoring	Resolved	2001-11-01 → 2001-11-30
MR	Monitoring	Resolved	2001-11-01 → 2001-11-30
MR	Monitoring	Resolved	2001-11-01 → 2001-11-30

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).

Contaminant	Max	Detection rate	Period
PFHXS	0.0033 µg/L	2/8	2024
Pfpea	0.0044 µg/L	2/8	2024

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
Copper	1080 µg/L 83% of the EPA limit 1300 µg/L worst single sample: 1880 µg/L	181/182	SYR4	2012–2017
Fluoride	838.9 µg/L 21% of the EPA limit 4000 µg/L worst single sample: 930 µg/L	103/200	SYR4	2012–2019
Lead	84 µg/L 560% of the EPA limit, at the 95th percentile of samples — 15 µg/L worst single sample: 426 µg/L	53/182	SYR4	2012–2017
Lead	0.0030 mg/L 20% of the EPA limit 0.0150 mg/L	24/24	LCR	2023
Nitrate-Nitrite	4812.5 µg/L 48% of the EPA limit 10000 µg/L worst single sample: 5110 µg/L	18/34	SYR4	2012–2019
Dibromochloromethane	4.2 µg/L No EPA limit set worst single sample: 7.2 µg/L	16/29	SYR4	2012–2019
Bromodichloromethane	4.31 µg/L No EPA limit set worst single sample: 6.4 µg/L	12/29	SYR4	2012–2019
Bromoform	3.44 µg/L No EPA limit set worst single sample: 4.6 µg/L	9/29	SYR4	2012–2019
Chloroform	4.28 µg/L No EPA limit set worst single sample: 5 µg/L	9/29	SYR4	2012–2019
Barium	26.24 µg/L 1.3% of the EPA limit 2000 µg/L worst single sample: 26.8 µg/L	8/8	SYR4	2014–2017
Nitrate	4280 µg/L 43% of the EPA limit 10000 µg/L	8/16	SYR4	2014–2017
TTHM	18.265 µg/L 23% of the EPA limit 80 µg/L worst single sample: 23.2 µg/L	8/10	SYR4	2013–2019
Combined Radium (-226 And -228)	4.08 pCi/L 82% of the EPA limit 5 pCi/L worst single sample: 4.23 pCi/L	6/6	SYR4	2014–2017
Gross Alpha, Excl. Radon And U	11.8 pCi/L 79% of the EPA limit 15 pCi/L worst single sample: 12 pCi/L	6/6	SYR4	2014–2017
Gross Beta Particle Activity	6.5975 pCi/L No EPA limit set worst single sample: 7.03 pCi/L	6/6	SYR4	2014–2017
Xylenes, Total	13.66 µg/L 0.1% of the EPA limit 10000 µg/L worst single sample: 15.4 µg/L	4/29	SYR4	2012–2019
Ethylbenzene	2.703 µg/L 0.4% of the EPA limit 700 µg/L worst single sample: 2.9 µg/L	3/29	SYR4	2012–2019
Combined Uranium	3.83 µg/L 13% of the EPA limit 30 µg/L worst single sample: 3.88 µg/L	2/2	SYR4	2014
Total Haloacetic Acids (HAA5)	1.38 µg/L 2.3% of the EPA limit 60 µg/L worst single sample: 1.4 µg/L	2/9	SYR4	2013–2019
Dibromoacetic Acid	1 µg/L No EPA limit set	1/9	SYR4	2013–2019
Dichloroacetic Acid	1.4 µg/L No EPA limit set	1/9	SYR4	2013–2019
Styrene	0.1000 µg/L 0.1% of the EPA limit 100 µg/L	1/29	SYR4	2012–2019
Tetrachloroethylene	0.1400 µg/L 2.8% of the EPA limit 5 µg/L	1/29	SYR4	2012–2019

80 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalArsenicAtrazineBhc-GammaBenzeneBeryllium, TotalChlorobenzeneCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDinosebDiquatEndothallEndrinGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidMonochloroacetic AcidNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPfmbaPfmpaPFNAPFOAPFOSPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineThallium, TotalTolueneToxapheneTrichloroacetic AcidTrichloroethyleneVinyl Chloridecis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Frequently asked questions about Mt Horeb Waterworks

Is Mt Horeb Waterworks tap water safe to drink?

EPA monitoring detected 25 contaminants in Mt Horeb 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 Mt Horeb Waterworks's water?

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

How many people does Mt Horeb Waterworks serve?

Mt Horeb Waterworks reports serving 7,756 people in Wisconsin, per its EPA record.

Has Mt Horeb Waterworks had any water quality violations?

The EPA has 180 violations on file for Mt Horeb Waterworks, of which 1 is health-based (a contaminant limit or required treatment was breached) and 1 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.