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Fort Defiance, Window Rock, St. Michaels, AZ

EPA monitoring detected 16 contaminants across the 1 water supplier serving Fort Defiance, Window Rock, St. Michaels. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
12,869
people served
16
contaminants found
Arizona rankings Lead in Arizona PFAS in Arizona

What was found in Fort Defiance, Window Rock, St. Michaels's water

The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
1100 µg/L 11%
of the EPA limit 10000 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Fluoride
570 µg/L 14%
of the EPA limit 4000 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Nitrite
455 µg/L 46%
of the EPA limit 1000 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Barium
226.2 µg/L 11%
of the EPA limit 2000 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Lithium
138 µg/L
No EPA limit set
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2025
1/1 UCMR-5
TTHM
128.15 µg/L 160%
of the EPA limit, at the 95th percentile of samples — 80 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Combined Uranium
37.53 µg/L 125%
of the EPA limit, at the 95th percentile of samples — 30 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
27.4 µg/L 46%
of the EPA limit 60 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Selenium
15 µg/L 30%
of the EPA limit 50 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Chromium
9.5 µg/L 9.5%
of the EPA limit 100 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Arsenic
7.695 µg/L 77%
of the EPA limit 10 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Gross Alpha, Excl. Radon And U
3.06 pCi/L 20%
of the EPA limit 15 pCi/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Combined Radium (-226 And -228)
1.53 pCi/L 31%
of the EPA limit 5 pCi/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Mercury
0.5000 µg/L 25%
of the EPA limit 2 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Beryllium, Total
0.2000 µg/L 5%
of the EPA limit 4 µg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2019
1/1 SYR4
Lead
0.0016 mg/L 11%
of the EPA limit 0.0150 mg/L
Main supplier: Fort Defiance-Window Rock-St Michaels NTUA · 12,869 people · 2025
1/1 LCR
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 the system's samples — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving Fort Defiance, Window Rock, St. Michaels

SupplierPopulation served
Fort Defiance-Window Rock-St Michaels NTUA 12,869

Frequently asked questions about Fort Defiance, Window Rock, St. Michaels tap water

Is Fort Defiance, Window Rock, St. Michaels tap water safe to drink?

EPA testing detected 16 contaminants in the water serving Fort Defiance, Window Rock, St. Michaels. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve Fort Defiance, Window Rock, St. Michaels?

1 public water supplier report drinking-water monitoring for Fort Defiance, Window Rock, St. Michaels, Arizona to the EPA. Each is listed above with its population served.

What contaminants are in Fort Defiance, Window Rock, St. Michaels's water?

The contaminants EPA monitoring detected in Fort Defiance, Window Rock, St. Michaels include Nitrate, Fluoride, Nitrite, Barium, Lithium. The full list, with the level at the main supplier and the data source, is in the table above.

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.