Molybdenum in Arizona Drinking Water
Ranked by max molybdenum detected (µg/L) · UCMR 3 data (2013–2015) · Data from EPA SDWIS & UCMR
Molybdenum in Arizona: what the data shows
Arizona has 58 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 6.02 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.
Cities exceeding 40 µg/L EPA lifetime HA (no MCL)
Molybdenum data across Arizona
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.
Top 10 cities by molybdenum level in Arizona
Highest Molybdenum levels (µg/L)
All Arizona cities ranked by molybdenum level
| # | City | Level | Level | Over HA? | Violations | Grade |
|---|---|---|---|---|---|---|
| 1 | Bullhead City | 19.00 µg/L | No | 57 | F | |
| 2 | Apache Junction | 18.00 µg/L | No | 18 | F | |
| 3 | Tucson | 15.00 µg/L | No | 150 | F | |
| 4 | Goodyear | 13.00 µg/L | No | 3 | F | |
| 5 | Green Valley | 12.00 µg/L | No | 9 | D | |
| 6 | San Luis | 12.00 µg/L | No | 8 | D | |
| 7 | Buckeye | 11.00 µg/L | No | 103 | F | |
| 8 | Kingman | 11.00 µg/L | No | 110 | D | |
| 9 | Yuma | 10.00 µg/L | No | 318 | F | |
| 10 | Fort Defiance, Window Rock, St. Michaels | 10.00 µg/L | No | 22 | B- | |
| 11 | Nogales | 9.30 µg/L | No | 39 | F | |
| 12 | Casa Grande | 9.20 µg/L | No | 44 | F | |
| 13 | Safford | 9.20 µg/L | No | 9 | D | |
| 14 | Buckeye-Sono | 9.10 µg/L | No | 2 | B- | |
| 15 | Surprise | 7.40 µg/L | No | 18 | F | |
| 16 | Chandler | 7.20 µg/L | No | 32 | F | |
| 17 | Catalina | 7.10 µg/L | No | 2 | D | |
| 18 | Lake Havasu City | 6.70 µg/L | No | 5 | D | |
| 19 | Litchfield Park | 6.60 µg/L | No | 21 | F | |
| 20 | Peoria | 6.30 µg/L | No | 13 | F | |
| 21 | Sahuarita | 6.30 µg/L | No | 19 | F | |
| 22 | El Mirage | 6.10 µg/L | No | 3 | D | |
| 23 | Mesa | 5.60 µg/L | No | 3 | F | |
| 24 | Phoenix | 5.40 µg/L | No | 59 | F | |
| 25 | Somerton | 5.40 µg/L | No | 17 | D | |
| 26 | Ganado, Cornfield, Steamboat, Woodspring | 5.40 µg/L | No | 4 | B+ | |
| 27 | Sacaton, Sacaton Flats,Upper San Tan, Bl | 5.11 µg/L | No | 11 | B | |
| 28 | Gilbert | 5.10 µg/L | No | 11 | F | |
| 29 | Scottsdale | 5.10 µg/L | No | 22 | F | |
| 30 | Johnson Ranch | 5.00 µg/L | No | 7 | D | |
| 31 | Sun City West | 5.00 µg/L | No | 3 | B+ | |
| 32 | Mohave Valley | 5.00 µg/L | No | 14 | F | |
| 33 | Vaya Chin, Hickiwan, San Simon Village/S | 5.00 µg/L | No | 1 | A- | |
| 34 | Avondale | 4.80 µg/L | No | 13 | C+ | |
| 35 | Glendale | 4.60 µg/L | No | 5 | F | |
| 36 | Fountain Hills | 4.60 µg/L | No | 21 | F | |
| 37 | Anthem | 4.60 µg/L | No | 1 | B | |
| 38 | Oro Valley | 4.50 µg/L | No | 11 | D | |
| 39 | Maricopa | 4.30 µg/L | No | 228 | D | |
| 40 | Red Rock | 3.52 µg/L | No | 1 | D+ | |
| 41 | Cave Creek | 3.40 µg/L | No | 25 | C- | |
| 42 | Prescott Valley | 3.30 µg/L | No | 6 | D | |
| 43 | Florence | 3.00 µg/L | No | 60 | F | |
| 44 | Tempe | 2.80 µg/L | No | 3 | D+ | |
| 45 | Douglas | 2.80 µg/L | No | 55 | D | |
| 46 | Sun City | 2.70 µg/L | No | 1 | B | |
| 47 | Salt River Indian Community | 2.60 µg/L | No | 22 | B | |
| 48 | Rio Rico | 2.30 µg/L | No | 4 | C | |
| 49 | Prescott | 2.20 µg/L | No | 33 | F | |
| 50 | Payson | 2.20 µg/L | No | 60 | F | |
| 51 | Cottonwood | 2.10 µg/L | No | 184 | D | |
| 52 | Sedona | 2.00 µg/L | No | 174 | F | |
| 53 | Holbrook | 1.80 µg/L | No | 6 | F | |
| 54 | Upper Fruitland, Nenahnezad, San Juan, N | 1.60 µg/L | No | 9 | B+ | |
| 55 | Upper Fruitland, Nenahnezad, San Juan, N | 1.60 µg/L | No | 9 | B+ | |
| 56 | Queen Creek | 1.30 µg/L | No | 14 | D | |
| 57 | Paradise Valley | 1.20 µg/L | No | 3 | C | |
| 58 | Globe | 1.00 µg/L | No | 46 | F |
Frequently asked questions about molybdenum in Arizona
Is molybdenum in Arizona 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 Arizona 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.