01The verdict: is Fort Defiance water safe?
Fort Defiance's drinking water has significant quality concerns based on EPA testing data. With a grade of F (43/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 875 residents using groundwater (wells).
Copper is over its legal limit
Measured at 1.68 mg/L against the EPA Action Level of 1.3 mg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓Lead is well under the limit
90th-percentile lead is 1.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓34 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Fort Defiance's drinking water received a grade of F (43 out of 100), indicating failing water quality. The city's 1 water system serves approximately 875 residents using purchased ground water.
Lead levels were measured at 1.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 176 violations on record, including 1 health-based violation. 43 remain unresolved.
Fort Defiance ranks #246 out of 271 cities in Arizona for water quality, placing it among the lowest-rated in the state. Fort Defiance purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition. As a small community water system, Fort Defiance may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities. The system has seen 34 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
02What's in Fort Defiance's water
Every contaminant flagged in Fort Defiance, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Over Limit — EPA Action Level: 1.3 mg/L
Exceeds the EPA action level. Copper leaches from household plumbing — flush taps for 30 seconds before drinking, and consider a certified filter.Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 1.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.68 | 1.3 | mg/L | Inorganic | Over Limit |
Cities ranked by 90th-percentile lead PF PFAS in Arizona
Cities ranked by compounds detected Cu Copper in Arizona
Cities ranked by 90th-percentile copper
03Fort Defiance's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 176 violations on record, including 1 health-based violation. 43 remain unresolved.
1 of the last ten years was clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 3 ppb since 1997. Latest reading: 1 ppb (2025) — 7% of the action level. Sampled at higher-risk homes (90th percentile).
1.7mg/L(2016)
One sampling round on record — 129% of the 1.3mg/L EPA action level. Sampled at higher-risk homes (90th percentile).
04Where Fort Defiance's water comes from
Fort Defiance purchases its water supply from a regional wholesale provider rather than treating raw water directly.
Purchased Groundwater
Water is bought from a regional wholesaler; quality starts at the supplier's intake and treatment.
Wholesale supplier
Primary treatment happens at the wholesaler; the local utility maintains disinfectant residual in its pipes.
1 system
1 water system, operated under local government ownership.
875 people
Residents served across Fort Defiance's service area.
Water quality depends on both the wholesaler's treatment standards and the condition of Fort Defiance's local distribution pipes and storage facilities. Purchased water systems are common in suburban areas and smaller communities that lack the infrastructure for independent treatment. The system is operated by local government ownership and serves approximately 875 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| Tsehootsooi Middle School | NN0400181 | 875 | Purchased Groundwater |
05Pressure on Fort Defiance's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Flood & storm history
6 federal disaster declarations on record for Apache County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Fort Defiance compares
Scores for nearby Arizona cities on one line, with the average marked.
dashed line = Arizona average (41/100)
Fort Defiance scores 43/100 — on par with the Arizona average of 41/100. It outscores 7 of 10 nearby cities. Full Arizona rankings →
37.5 / 100FTucson, AZ
38.1 / 100FMesa, AZ
40.6 / 100FChandler, AZ
40.5 / 100FGilbert, AZ
34.8 / 100FScottsdale, AZ
43 / 100
07What to do at home
Steps matched to what testing actually found in Fort Defiance's water — not generic advice.
Filter drinking & cooking water
NSF-certified water filter. Copper exceeds the EPA action level of 1.3 mg/L
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Fort Defiance alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Fort Defiance, AZ tap water safe to drink?
Fort Defiance's water quality earned a grade of F (43/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #246 out of 271 cities tested in Arizona.
What contaminants are in Fort Defiance's water?
Lead was measured at 1.0 ppb (90th percentile). 176 violations are on record.
How is Fort Defiance's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Fort Defiance?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Fort Defiance's water come from?
Fort Defiance's water is sourced from Purchased ground water. The city has 1 water system serving approximately 875 residents.
What health violations has Fort Defiance's water system had?
Fort Defiance has 1 health-based violation on record. The most recent violation was recorded in August 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 43 violations remain unresolved.
Is Fort Defiance's groundwater at risk of contamination?
Fort Defiance uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 176 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Fort Defiance's water compare to other cities?
Fort Defiance ranks #246 out of 271 cities in Arizona (better than 9% of state cities) and #14391 out of 15382 cities nationally (6th percentile). The grade of F reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Fort Defiance's small water system affect quality?
Fort Defiance's system serves approximately 875 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 176 violations on record.