Is Williams, AZ Tap Water Safe to Drink?
Graded D+, with 33 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
50/100
waterverge.com Williams, AZ — Water Quality Report
Williams's drinking water received a grade of D+ (50 out of 100), indicating poor water quality. The city's 3 water systems serve approximately 4,623 residents using groundwater.
Lead levels were measured at 0.0 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 266 violations on record, including 14 health-based violations. 33 remain unresolved.
What to know about Williams's water
Williams ranks #185 out of 292 cities in Arizona for water quality, placing it below average in the state.
Williams 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.
The system has seen 42 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Williams, AZ water safe to drink?
Williams's drinking water has significant quality concerns based on EPA testing data. With a grade of D+ (50/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 4,623 residents using groundwater (wells).
Recent water quality updates for Williams
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Williams's water quality assessment. Grade: D+ (50/100).
Contaminants: Surface Water Treatment Rule, Interim Enhanced Surface Water Treatment Rule.
Contaminants: Revised Total Coliform Rule.
1 health-based. Contaminants: Public Notice, Arsenic.
Federal disaster declaration (FEMA DR-4620). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3241). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Williams's water supply.
Well within EPA limits.
Violation history
Williams's water system has 266 total violations on record, including 14 health-based violations. 33 remain unresolved. 42 violations were issued in the last 5 years.
Flood & environmental risk
Coconino County has experienced 6 federally declared disasters since 1970. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Williams's water come from?
Williams's drinking water comes from groundwater (wells), supplied by 3 water systems serving approximately 4,623 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Williams residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Williams's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Williams's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D2 — severe droughtCoconino County is currently in D2 (severe drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Coconino County has experienced 6 federally declared disasters since 1970. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Williams compares by contaminant
Explore where Williams ranks among all Arizona cities for specific contaminants.
Water source & infrastructure
Where Williams's water comes from
Williams's drinking water is drawn from underground aquifers through wells.
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 local government ownership and serves approximately 4,623 people through 3 water systems.
Water systems serving Williams
| System Name | PWSID | Population | Source |
|---|---|---|---|
| WILLIAMS CITY OF | AZ0403026 | 3,145 | GW |
| BEARIZONA | AZ0403105 | 1,423 | GW |
| CAMP WATERMAN MWC | CA3600064 | 55 | GW |
How Williams compares
Full Arizona rankings →Williams's score of 50/100 is above the average of 42/100 among major Arizona cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Arizona rankings →About Williams, AZ
Wikipedia →Williams is a city in Coconino County, Arizona, United States, located west of Flagstaff. As of the 2020 census, Williams had a population of 3,202. It lies on the routes of Historic Route 66 and Interstate 40. It is also the southern terminus of the Grand Canyon Railway, which takes visitors to Grand Canyon Village.
Learn more about your water
Guides and resources related to Williams's water quality findings.
Explore water quality across Coconino
Frequently asked questions
Is Williams, AZ tap water safe to drink?
Williams's water quality earned a grade of D+ (50/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #185 out of 292 cities tested in Arizona.
What contaminants are in Williams's water?
Lead was measured at 0.0 ppb (90th percentile). 266 violations are on record.
How is Williams'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 Williams?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Williams's water come from?
Williams's water is sourced from Groundwater. The city has 3 water systems serving approximately 4,623 residents.
What health violations has Williams's water system had?
Williams has 14 health-based violations on record. The most recent violation was recorded in December 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 33 violations remain unresolved.
Is Williams's groundwater at risk of contamination?
Williams 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 266 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 Williams's water compare to other cities?
Williams ranks #185 out of 292 cities in Arizona (better than 37% of state cities) and #13071 out of 15744 cities nationally (17th percentile). The grade of D+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.