Is Fort Defiance-Window Rock-St Michaels Ntua Tap Water Safe? Quality Report

Water source: Ground water
Ownership: Native American

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

233

violations on file

still open

Violation	Type	Status	Period
TT	Health-based	Resolved	2025-02-01
TT	Health-based	Resolved	2025-02-01
TT	Health-based	Resolved	2025-02-01
MCL	Health-based	Resolved	2024-10-01 → 2024-12-31
MCL	Health-based	Resolved	2024-10-01 → 2024-12-31
MCL	Health-based	Resolved	2024-10-01 → 2024-12-31
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2017-01-01 → 2017-03-31
MCL	Health-based	Resolved	2016-10-01 → 2016-12-31

Other contaminants detected

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 this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
TTHM	128.15 µg/L 160% of the EPA limit, at the 95th percentile of samples — 80 µg/L worst single sample: 154 µg/L	108/116	SYR4	2012–2019
Nitrate	1100 µg/L 11% of the EPA limit 10000 µg/L worst single sample: 1200 µg/L	88/206	SYR4	2012–2019
Total Haloacetic Acids (HAA5)	27.4 µg/L 46% of the EPA limit 60 µg/L worst single sample: 30.7 µg/L	71/116	SYR4	2012–2019
Barium	226.2 µg/L 11% of the EPA limit 2000 µg/L worst single sample: 284 µg/L	18/25	SYR4	2012–2019
Fluoride	570 µg/L 14% of the EPA limit 4000 µg/L	18/24	SYR4	2012–2019
Nitrite	455 µg/L 46% of the EPA limit 1000 µg/L worst single sample: 490 µg/L	15/103	SYR4	2012–2019
Combined Uranium	37.53 µg/L 125% of the EPA limit, at the 95th percentile of samples — 30 µg/L worst single sample: 38.7 µg/L	14/15	SYR4	2012–2019
Lead	0.0016 mg/L 11% of the EPA limit 0.0150 mg/L	14/14	LCR	2025
Lithium	138 µg/L No EPA limit set	12/14	UCMR-5	2025
Chromium	9.5 µg/L 9.5% of the EPA limit 100 µg/L worst single sample: 10 µg/L	11/24	SYR4	2012–2019
Selenium	15 µg/L 30% of the EPA limit 50 µg/L	9/22	SYR4	2012–2019
Arsenic	7.695 µg/L 77% of the EPA limit 10 µg/L worst single sample: 7.8 µg/L	8/22	SYR4	2012–2019
Gross Alpha, Excl. Radon And U	3.06 pCi/L 20% of the EPA limit 15 pCi/L worst single sample: 3.2 pCi/L	8/15	SYR4	2012–2019
Combined Radium (-226 And -228)	1.53 pCi/L 31% of the EPA limit 5 pCi/L worst single sample: 1.8 pCi/L	7/15	SYR4	2012–2019
Beryllium, Total	0.2000 µg/L 5% of the EPA limit 4 µg/L	5/25	SYR4	2012–2019
Mercury	0.5000 µg/L 25% of the EPA limit 2 µg/L	5/16	SYR4	2013–2019

85 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,3,7,8-TCDD2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneChlorobenzeneCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMethoxychlorNetfosaaNfdhaNmefosaaOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact: David Shoultz
Phone: 9287296277
Email: [email protected]

Frequently asked questions about Fort Defiance-Window Rock-St Michaels Ntua

Is Fort Defiance-Window Rock-St Michaels Ntua tap water safe to drink?

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

What contaminants were detected in Fort Defiance-Window Rock-St Michaels Ntua's water?

EPA monitoring detected TTHM, Nitrate, Total Haloacetic Acids (HAA5), Barium, Fluoride, and others. The full list with the level and data source for each is above.

How many people does Fort Defiance-Window Rock-St Michaels Ntua serve?

Fort Defiance-Window Rock-St Michaels Ntua reports serving 12,869 people in Arizona, per its EPA record.

Has Fort Defiance-Window Rock-St Michaels Ntua had any water quality violations?

The EPA has 233 violations on file for Fort Defiance-Window Rock-St Michaels Ntua, of which 47 are health-based (a contaminant limit or required treatment was breached) and 2 remain open. The rest are monitoring or reporting failures.

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.