Molybdenum Contamination

Molybdenum in Wisconsin Drinking Water

Ranked by max molybdenum detected (µg/L) · UCMR 3 data (2013–2015) · Data from EPA SDWIS & UCMR

Cities Tested

Over HA

% Over HA

1.80 µg/L

State Avg

▼ 2% vs national

vs National

388

Health Violations

Analysis

Molybdenum in Wisconsin: what the data shows

Wisconsin has 42 cities with molybdenum data from the EPA's UCMR 3 program (2013–2015). Molybdenum exceeded the 40 µg/L EPA lifetime health advisory in 0 of those cities. The state average max detected level is 1.80 µg/L. Molybdenum is a naturally occurring trace element found in groundwater across the western United States, particularly in areas with shale or copper-mining geology. Industrial sources include mining, steel alloy production, and coal-fired power plants. There is no federal MCL — the EPA lifetime health advisory is 40 µg/L. Molybdenum is an essential nutrient at low doses, but chronic excess intake from drinking water has been linked to elevated uric acid, gout-like symptoms, and possible reproductive effects. Reverse osmosis is the most effective household treatment.

Comparison

Cities exceeding 40 µg/L EPA lifetime HA (no MCL)

Wisconsin

0 of 42 cities

← ▼ 2% below national rate (better)

National avg

36 of 2228 cities

City Map

Molybdenum data across Wisconsin

Each dot is a city with UCMR 3 molybdenum testing data. Cities where molybdenum exceeds the 40 µg/L EPA lifetime health advisory are highlighted. Size reflects population served.

Worst Offenders

Top 10 cities by molybdenum level in Wisconsin

Highest Molybdenum levels (µg/L)

All Cities

All Wisconsin cities ranked by molybdenum level

#	City	Level	Over HA?	Violations	Grade
1	Brookfield	14.52 µg/L	No	32	C-
2	Wrightstown	4.42 µg/L	No	4	B
3	Menomonee Falls	3.80 µg/L	No	6	B+
4	Beloit	3.53 µg/L	No	2	B+
5	Grafton	2.63 µg/L	No	12	C+
6	Manawa	2.36 µg/L	No	2	B
7	Fond Du Lac	2.14 µg/L	No	51	F
8	De Pere	1.85 µg/L	No	38	B
9	Green Bay	1.75 µg/L	No	74	D+
10	Little Chute	1.60 µg/L	No	1	B+
11	Whitewater	1.55 µg/L	No	22	C+
12	Hudson	1.44 µg/L	No	4	B
13	Sheboygan	1.40 µg/L	No	1	A-
14	Watertown	1.38 µg/L	No	10	D
15	Waukesha	1.33 µg/L	No	320	D
16	Caledonia	1.33 µg/L	No	1	B
17	Cedarburg	1.33 µg/L	No	1	B+
18	River Falls	1.22 µg/L	No	14	C+
19	Oconomowoc	1.22 µg/L	No	13	B
20	Manitowoc	1.20 µg/L	No	0	B+
21	Kenosha	1.19 µg/L	No	11	D
22	Germantown	1.18 µg/L	No	8	B-
23	Brown Deer	1.16 µg/L	No	5	A
24	Cudahy	1.13 µg/L	No	0	B+
25	Racine	1.10 µg/L	No	4	C+
26	Milwaukee	1.10 µg/L	No	2	A
27	La Crosse	1.10 µg/L	No	34	F
28	Glendale	1.10 µg/L	No	1	A-
29	Oak Creek	1.10 µg/L	No	5	B
30	Whitefish Bay	1.10 µg/L	No	0	B+
31	Port Washington	1.10 µg/L	No	6	B+
32	South Milwaukee	1.09 µg/L	No	0	A-
33	Franklin	1.09 µg/L	No	10	B
34	Shorewood	1.08 µg/L	No	1	A-
35	Two Rivers	1.06 µg/L	No	5	C-
36	Sheboygan Falls	1.03 µg/L	No	5	B-
37	Marinette	1.02 µg/L	No	0	A-
38	West Allis	1.02 µg/L	No	0	A-
39	Greendale	1.02 µg/L	No	1	A-
40	Kiel	1.02 µg/L	No	3	A-
41	New Berlin	1.01 µg/L	No	14	B
42	Bowler	1.00 µg/L	No	8	A-

FAQ

Frequently asked questions about molybdenum in Wisconsin

Is molybdenum in Wisconsin tap water harmful?

Molybdenum is an essential trace nutrient at low levels, but chronic exposure above the EPA's 40 µg/L lifetime health advisory has been associated with elevated uric acid, gout-like joint pain, and possible reproductive effects. No cities in Wisconsin exceed the 40 µg/L health advisory.

Where does molybdenum come from?

Molybdenum occurs naturally in groundwater, especially in the western US in regions with shale, copper mining, or molybdenum mining geology. Industrial sources include mining tailings, steel alloy production, and coal ash. Surface-water systems generally have lower molybdenum than groundwater.

How can I remove molybdenum from drinking water?

Reverse osmosis is the most effective household treatment for molybdenum, typically removing 90%+. Anion exchange and some specialty media (like activated alumina) also work. Standard activated carbon filters are NOT effective against molybdenum.

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