Question 1

Which county in Wisconsin has the best water quality?

Accepted Answer

Brown County has the highest water quality score in Wisconsin at 100.0/100 (Grade: B), based on EPA SDWIS data.

Question 2

Which county in Wisconsin has the most water violations?

Accepted Answer

Adams County has among the lowest water quality scores in Wisconsin at 95.1/100. See the individual county page for detailed violation history.

Question 3

Is the tap water safe to drink in Wisconsin?

Accepted Answer

Wisconsin has an average water quality score of 99.7/100 based on EPA Safe Drinking Water Act compliance data. Individual county scores vary — check your specific county's page for detailed information.

Question 4

What contaminants are found in Wisconsin water supplies?

Accepted Answer

Drinking water quality varies by county and water system. The EPA Safe Drinking Water Information System (SDWIS) tracks violations for contaminants like lead, nitrates, bacteria, and disinfection byproducts. See individual county pages for specific contaminant and violation history.

County	Water Score	Grade	Violations	Violation Rate
Brown County	100.0	B	12	5.0%
Chippewa County	100.0	C	3	9.6%
Dane County	100.0	B	17	3.5%
Door County	100.0	A	0	0.0%
Fond du Lac County	100.0	C	4	6.2%
La Crosse County	100.0	C	5	5.4%
Milwaukee County	100.0	A	3	0.3%
Outagamie County	100.0	B	5	2.9%
Portage County	100.0	B	1	2.3%
Racine County	100.0	B	7	4.6%
Rock County	100.0	C	11	8.8%
Sheboygan County	100.0	C	5	5.7%
Washington County	100.0	B	4	4.6%
Waupaca County	100.0	C	2	7.9%
Wood County	100.0	B	1	2.2%
Barron County	99.9	D	5	23.6%
Burnett County	99.9	D	1	29.0%
Calumet County	99.9	D	5	23.1%
Dunn County	99.9	D	4	18.8%
Eau Claire County	99.9	C	10	11.7%
Green Lake County	99.9	D	2	21.7%
Juneau County	99.9	F	4	32.7%
Kenosha County	99.9	D	21	17.8%
Kewaunee County	99.9	D	2	22.5%
Lincoln County	99.9	D	3	22.4%
Manitowoc County	99.9	C	8	14.0%
Marathon County	99.9	D	14	15.1%
Ozaukee County	99.9	D	15	23.5%
Pierce County	99.9	D	5	18.7%
Polk County	99.9	D	4	25.3%
Sauk County	99.9	D	10	24.7%
Shawano County	99.9	D	5	24.9%
St. Croix County	99.9	C	5	11.5%
Walworth County	99.9	D	19	27.2%
Waushara County	99.9	F	2	31.8%
Winnebago County	99.9	D	28	19.3%
Bayfield County	99.8	F	2	49.2%
Buffalo County	99.8	F	2	41.5%
Douglas County	99.8	F	14	52.8%
Green County	99.8	F	8	34.2%
Marinette County	99.8	F	10	52.5%
Monroe County	99.8	F	13	39.2%
Oneida County	99.8	F	5	41.8%
Dodge County	99.7	F	30	57.5%
Grant County	99.7	F	26	76.1%
Jackson County	99.7	F	6	65.7%
Jefferson County	99.7	F	45	73.0%
Oconto County	99.7	F	6	58.3%
Price County	99.7	F	3	54.8%
Richland County	99.7	F	4	56.6%
Trempealeau County	99.7	F	12	71.3%
Washburn County	99.7	F	3	61.2%
Langlade County	99.6	F	8	93.8%
Clark County	99.5	F	11	109.6%
Columbia County	99.5	F	41	107.5%
Lafayette County	99.5	F	8	101.8%
Vernon County	99.5	F	14	109.5%
Crawford County	99.4	F	11	120.1%
Forest County	99.4	F	5	127.1%
Iron County	99.4	F	5	140.3%
Marquette County	99.4	F	2	132.0%
Taylor County	99.4	F	8	125.0%
Vilas County	99.4	F	4	124.8%
Waukesha County	99.4	F	340	136.8%
Iowa County	99.3	F	22	161.5%
Sawyer County	99.3	F	6	154.7%
Pepin County	98.8	F	7	255.1%
Rusk County	98.8	F	13	266.8%
Florence County	98.6	F	4	312.5%
Ashland County	98.4	F	35	356.6%
Adams County	95.1	F	80	1065.1%
Menominee County	—	—	—	—

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