Wisconsin utilities with very hard water.

Above 180 mg/L (10.5 grains per gallon). 580 utilities serving 1.6 million people as they report it, largest first.

101 to 200 of 580, by people served

Wisconsin utilities with very hard water, 101 to 200, 101 to 200
Utility	Based in	Serves	Hardness, mg/L	Grains per gallon
Poynette Waterworks	Poynette	2,520	260	15.2
Deerfield Waterworks	Deerfield	2,510	340	19.9
Fennimore Waterworks	Fennimore	2,507	323	18.9
Belgium Waterworks	Belgium	2,493	300	17.5
Mineral Point Waterworks	Mineral Point	2,487	375	21.9
Dousman Water Utility	Dousman	2,350	285	16.7
New Glarus Waterworks	New Glarus	2,348	305	17.8
Walworth Waterworks	Walworth	2,304	350	20.5
Fredonia Waterworks	Fredonia	2,279	398	23.2
Geneva National Community Services	Lake Geneva	2,250	360	21.1
Darlington Waterworks	Darlington	2,235	310	18.1
Cedar Grove Waterworks	Cedar Grove	2,213	372	21.8
Schofield Waterworks	Schofield	2,205	210	12.3
Pardeeville Waterworks	Pardeeville	2,151	277	16.2
Cuba City Waterworks	Cuba City	2,141	375	21.9
Clinton Waterworks	Clinton	2,119	300	17.5
Prairie Village Water Trust	North Prairie	2,100	380	22.2
Crandon Waterworks	Crandon	1,958	258	15.1
Eagle Waterworks	Eagle	1,950	365	21.3
Harmony Grove San Dist	Lodi	1,950	223	13
Trempealeau Waterworks	Trempealeau	1,888	188	11
Hammond Waterworks	Hammond	1,884	211	12.3
Roberts Waterworks	Roberts	1,872	216	12.6
Durand Waterworks	Durand	1,868	244	14.3
Fox Lake Correctional Institution	Fox Lake	1,850	265	15.5
Fontana Water Utility	Fontana	1,839	370	21.6
Campbellsport Waterworks	Campbellsport	1,825	424	24.8
Weyauwega Waterworks	Weyauwega	1,820	319	18.7
Randolph Water Dept	Randolph	1,800	306	17.9
Menomonee Falls Ww - Groundwater	Menomonee Falls	1,796	355	20.8
Fall River Waterworks	Fall River	1,793	308	18
Palmyra Waterworks	Palmyra	1,756	360	21.1
Mazomanie Waterworks	Mazomanie	1,744	309	18.1
Whiting Waterworks	Stevens Point	1,743	305	17.8
Stratford Waterworks	Stratford	1,643	288	16.8
Cambridge Water & Sewer Utility	Cambridge	1,638	245	14.3
Spring Green Waterworks	Spring Green	1,626	242	14.2
Fox Lake Waterworks	Fox Lake	1,610	310	18.1
Random Lake Waterworks	Random Lake	1,594	515	30.1
Darien Waterworks	Darien	1,573	305	17.8
Elkhart Lake Waterworks	Elkhart Lake	1,567	345	20.2
Niagara Waterworks	Niagara	1,561	208	12.1
Federal Correctional Institution	Oxford	1,550	252	14.7
Sharon Waterworks	Sharon	1,549	360	21.1
Kettle Moraine Correctional Institution	Plymouth	1,544	370	21.6
Brooklyn Waterworks	Brooklyn	1,524	308	18
Cleveland Waterworks	Cleveland	1,524	382	22.3
Bangor Waterworks	Bangor	1,520	255	14.9
Concordia University	Mequon	1,500	240	14
Black Earth Waterworks	Black Earth	1,493	288	16.8
Bonduel Waterworks	Bonduel	1,475	345	20.2
Orfordville Waterworks	Orfordville	1,475	308	18
Muscoda Waterworks	Muscoda	1,453	218	12.7
Mishicot Waterworks	Mishicot	1,432	390	22.8
West Baraboo Waterworks	West Baraboo	1,414	204	11.9
Markesan Waterworks	Markesan	1,365	310	18.1
Black Creek Waterworks	Black Creek	1,336	245	14.3
Montello Waterworks	Montello	1,329	240	14
Manawa Waterworks	Manawa	1,300	290	17
Marion Waterworks	Marion	1,293	410	24
Gillett Waterworks	Gillett	1,264	260	15.2
Theresa Waterworks	Theresa	1,262	328	19.2
Barneveld Waterworks	Barneveld	1,258	356	20.8
Florence Utility Commission	Florence	1,250	260	15.2
Iola Waterworks	Iola	1,249	366	21.4
Shullsburg Waterworks	Shullsburg	1,222	310	18.1
Monticello Waterworks	Monticello	1,217	290	17
Lakeland University	Plymouth	1,200	283	16.5
Reedsville Waterworks	Reedsville	1,200	438	25.6
Rockvale MHP	Janesville	1,200	270	15.8
Wittenberg Waterworks	Wittenberg	1,200	390	22.8
Hazel Green Waterworks	Hazel Green	1,193	325	19
Hilbert Waterworks	Hilbert	1,176	402	23.5
Princeton Waterworks	Princeton	1,166	268	15.7
Luck Waterworks	Luck	1,150	233	13.6
Amherst Waterworks	Amherst	1,119	275	16.1
Dane Waterworks	Dane	1,117	250	14.6
Oakhill Correctional Inst	Oregon	1,096	319	18.6
Rio Waterworks	Rio	1,095	247	14.4
Dickeyville Waterworks	Dickeyville	1,069	359	21
Robert William Park Water Association Inc	Milwaukee	1,065	500	29.2
Clear Lake Waterworks	Clear Lake	1,061	214	12.5
Oakfield Waterworks	Oakfield	1,058	324	18.9
Boyceville Waterworks	Boyceville	1,043	228	13.3
Crivitz Waterworks	Crivitz	1,026	268	15.6
Shelby TN of Wedgewood Vly	La Crosse	1,020	235	13.7
Albany Waterworks	Albany	1,018	314	18.4
Green Lake Waterworks	Green Lake	1,002	382	22.4
Sister Bay Waterworks	Sister Bay	1,000	335	19.6
Belmont Waterworks	Belmont	989	333	19.5
Benton Waterworks	Benton	976	455	26.6
Valders Waterworks	Valders	954	444	26
Blue Mounds Waterworks	Blue Mounds	950	335	19.6
Southern Wisconsin Center	Union Grove	950	244	14.3
Wisconsin Veterans Home	King	950	280	16.4
Arlington Waterworks	Arlington	946	400	23.4
Paddock Lake Waterworks	Paddock Lake	945	290	17
Iron Ridge Waterworks	Iron Ridge	937	328	19.2
Dresser Waterworks	Dresser	936	208	12.1
Plainfield Waterworks	Plainfield	924	265	15.5

Source: Wisconsin Department of Natural Resources, Drinking Water Program, 940 utilities, results from Feb. 4, 2015 to Sept. 24, 2026, read Oct. 10, 2026. Each sampling point is taken at its median; a figure is typical where every point falls in one band.

Bands are the U.S. Geological Survey’s, at 17.1 mg/L to the grain. People served is what each utility reports; where one sells water to another, the same people can be counted twice. How hardness is measured here.

101 to 200 of 580, by people served

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