Is Mammoth, AZ Tap Water Safe to Drink?
Graded C- — but Lead was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
57.8/100
waterverge.com Mammoth, AZ — Water Quality Report
Mammoth's drinking water received a grade of C- (57.8 out of 100), indicating poor water quality. The city's 1 water system serves approximately 1,181 residents using groundwater.
Lead levels were measured at 19.0 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 102 violations on record, including 2 health-based violations. 23 remain unresolved.
What to know about Mammoth's water
Mammoth ranks #168 out of 292 cities in Arizona for water quality, placing it below average in the state.
Mammoth 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.
As a small community water system, Mammoth may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 11 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Mammoth, AZ water safe to drink?
Mammoth's drinking water has significant quality concerns based on EPA testing data. With a grade of C- (57.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,181 residents using groundwater (wells).
Recent water quality updates for Mammoth
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Mammoth's water quality assessment. Grade: C- (57.8/100).
Contaminants: Public Notice.
Contaminants: Consumer Confidence Rule.
Contaminants: LEAD AND COPPER RULE REVISIONS.
Federal disaster declaration (FEMA DR-3241). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-977). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Mammoth's water supply.
Exceeds EPA action level. Lead service line replacement and point-of-use filtration recommended.
Violation history
Mammoth's water system has 102 total violations on record, including 2 health-based violations. 23 remain unresolved. 11 violations were issued in the last 5 years.
Flood & environmental risk
Pinal County has experienced 7 federally declared disasters since 1966. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Aravaipa Creek.
Where does Mammoth's water come from?
Mammoth's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,181 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Aravaipa Creek (river).
What Mammoth residents can do
Recommended: NSF 53-certified pitcher or under-sink filter. This addresses the specific contaminants found in Mammoth'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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Mammoth'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 droughtPinal 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
Pinal County has experienced 7 federally declared disasters since 1966. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Mammoth's water supply, we recommend the following filter types.
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. | 19.0 | 15 | ppb | Inorganic | Over Limit |
Lead level trend (90th percentile)
See how Mammoth compares by contaminant
Explore where Mammoth ranks among all Arizona cities for specific contaminants.
Water source & infrastructure
Where Mammoth's water comes from
Mammoth'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 1,181 people through 1 water system.
Water bodies near Mammoth
Mammoth is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Mammoth
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MAMMOTH TOWN OF | AZ0411018 | 1,181 | GW |
How Mammoth compares
Full Arizona rankings →Mammoth's score of 57.8/100 is above the average of 42/100 among major Arizona cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Arizona rankings →About Mammoth, AZ
Learn more about your water
Guides and resources related to Mammoth's water quality findings.
Explore water quality across Pinal
Frequently asked questions
Is Mammoth, AZ tap water safe to drink?
Mammoth's water quality earned a grade of C- (57.8/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #168 out of 292 cities tested in Arizona.
What contaminants are in Mammoth's water?
Lead was measured at 19.0 ppb (90th percentile). 102 violations are on record.
How is Mammoth'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 Mammoth?
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 Mammoth's water come from?
Mammoth's water is sourced from Groundwater. The city has 1 water system serving approximately 1,181 residents.
What health violations has Mammoth's water system had?
Mammoth has 2 health-based violations on record. The most recent violation was recorded in November 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 23 violations remain unresolved.
Is Mammoth's groundwater at risk of contamination?
Mammoth 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 102 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 Mammoth's water compare to other cities?
Mammoth ranks #168 out of 292 cities in Arizona (better than 42% of state cities) and #12346 out of 15744 cities nationally (22th percentile). The grade of C- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Mammoth's small water system affect quality?
Mammoth's system serves approximately 1,181 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 102 violations on record.