01The verdict: is Pima water safe?
Pima's drinking water has significant quality concerns based on EPA testing data. With a grade of F (29/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 4,561 residents using groundwater (wells).
Lead is over its legal limit
Measured at 32.0 ppb against the EPA Action Level of 15 ppb. The ledger below shows how far over — and which filter removes it.
See the measurement ↓5K people, 3 systems
All figures on this page come from federal EPA compliance and testing data for the systems serving this city.
See the systems ↓41 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 ↓Pima's drinking water received a grade of F (29 out of 100), indicating failing water quality. The city's 3 water systems serve approximately 4,561 residents using groundwater.
Lead levels were measured at 32.0 ppb (90th percentile), which exceeds the EPA action level of 15 ppb. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 324 violations on record, including 11 health-based violations. 66 remain unresolved.
Pima ranks #271 out of 271 cities in Arizona for water quality, placing it among the lowest-rated in the state. Pima relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. Lead levels exceed the EPA action level of 15 ppb, which typically indicates aging lead service lines or lead solder in the distribution system. An NSF 53-certified filter is strongly recommended for drinking and cooking water. The system has seen 41 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
02What's in Pima's water
Every contaminant flagged in Pima, 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: 15 ppb
Exceeds the EPA action level. Lead enters at the service line, not the treatment plant — your address matters more than the city average. Lead service line replacement and an NSF 53-certified point-of-use filter are recommended.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. | 32.0 | 15 | ppb | 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
03Pima'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 324 violations on record, including 11 health-based violations. 66 remain unresolved.
3 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▲ Up 30 ppb since 2003. The latest reading (32 ppb, 2027) is over the action level. Sampled at higher-risk homes (90th percentile).
04Where Pima's water comes from
Pima's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
3 systems
3 water systems, operated under private ownership.
4,561 people
Residents served across Pima's service area.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by private ownership and serves approximately 4,561 people through 3 water systems.
| System name | PWSID | Population | Source |
|---|---|---|---|
| GRAHAM COUNTY UTILITIES - PIMA | AZ0405002 | 3,799 | Groundwater |
| GRAHAM COUNTY UTILITIES-FORT THOMAS | AZ0405001 | 452 | Groundwater |
| ASH CREEK WATER COMPANY | AZ0405007 | 310 | Groundwater |
05Pressure on Pima'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
8 federal disaster declarations on record for Graham County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Graham County is in D2 (severe drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Pima compares
Scores for nearby Arizona cities on one line, with the average marked.
dashed line = Arizona average (41/100)
Pima scores 29/100 — below the Arizona average of 41/100. 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
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Pima's water — not generic advice.
Filter drinking & cooking water
NSF 53-certified pitcher or under-sink filter. Lead level (32.0 ppb) exceeds the EPA action level of 15 ppb
Compare tested filters →Flush taps & check your service line
Lead leaches from pipes as water sits. Run cold water 30 seconds before drinking (especially mornings), and ask the utility whether your address still has a lead service line.
Lead risks explained →Watch for Pima 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 Pima, AZ tap water safe to drink?
Pima's water quality earned a grade of F (29/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #271 out of 271 cities tested in Arizona.
What contaminants are in Pima's water?
Lead was measured at 32.0 ppb (90th percentile). 324 violations are on record.
How is Pima'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 Pima?
Yes — lead levels exceed the EPA action level of 15 ppb. We recommend an NSF 53-certified filter or reverse osmosis system. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Pima's water come from?
Pima's water is sourced from Groundwater. The city has 3 water systems serving approximately 4,561 residents.
What health violations has Pima's water system had?
Pima has 11 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 66 violations remain unresolved.
Is Pima's groundwater at risk of contamination?
Pima 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 324 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 Pima's water compare to other cities?
Pima ranks #271 out of 271 cities in Arizona (better than 0% of state cities) and #15349 out of 15382 cities nationally (0th percentile). The grade of F reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.