WaterVerge

Is Mariano Lake, Pinedale, Churchrock, AZ Tap Water Safe to Drink?

Graded B+, with 2 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓

5K residents served 1 water system PWSID: NN3500211
Overall Score
84.5 / 100
Violations
2 active
Last Updated
May 2026
Source
Groundwater
#89 of 292 in Arizona Top 37% nationally
Native American
High data confidence
Reviewed by WaterVerge Editorial Team · Last updated May 2026
B+GRADE
Water Quality Grade
84.5/100
waterverge.com
B+ 84.5/100

Mariano Lake, Pinedale, Churchrock, AZ — Water Quality Report

Mariano Lake, Pinedale, Churchrock's drinking water received a grade of B+ (84.5 out of 100), indicating good water quality. The city's 1 water system serves approximately 4,562 residents using groundwater.

Lead levels were measured at 12.0 ppb (90th percentile), which is within EPA limits but above recommended levels. UCMR 5 testing detected 1 PFAS compound in the water supply.

The system has 35 violations on record, including 4 health-based violations. 2 remain unresolved.

Data last updated: May 2026 · Source: EPA SDWIS, UCMR 5
Analysis

What to know about Mariano Lake, Pinedale, Churchrock's water

Mariano Lake, Pinedale, Churchrock ranks #89 out of 292 cities in Arizona for water quality, placing it mid-range in the state.

Mariano Lake, Pinedale, Churchrock 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.

PFAS compounds were detected in testing, though levels remain within current EPA limits. Residents seeking extra precaution may consider an activated carbon or reverse osmosis filter.

While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.

Quality Breakdown

Water quality score

See methodology →
84.5 out of 100 Grade B+
A: 90-100
B: 74-89
C: 60-73
F: <50
How is this calculated?
Violations
41.3/45
A
Historical violation record including health-based and monitoring violations.
Lead & Copper
13/20
C
Lead at 12.0 ppb (90th percentile).
Contaminants
17.2/20
B
1 PFAS compound detected.
Compliance
8/10
B
Monitoring and reporting compliance with EPA regulations.
Source Risk
5/5
A
Water source: Groundwater.
Water Safety

Is Mariano Lake, Pinedale, Churchrock, AZ water safe to drink?

Use Caution

Mariano Lake, Pinedale, Churchrock's tap water meets most EPA standards but has areas that warrant attention. With a grade of B+ (84.5/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 4,562 residents using groundwater (wells).

2
Active Violations
12.0 ppb
Lead (90th %ile)
1 compound
PFAS Detected
6 events
Disaster History

Recent water quality updates for Mariano Lake, Pinedale, Churchrock

A timeline of significant water quality events, violations, and data updates.

PFAS
1 PFAS "forever chemical" compound detected

Detected at levels within current EPA limits. PFAS persist indefinitely in the environment.

Update
Water quality data updated

Latest EPA compliance and testing data incorporated into Mariano Lake, Pinedale, Churchrock's water quality assessment. Grade: B+ (84.5/100).

Disaster
SEVERE STORMS AND FLOODING

Federal disaster declaration (FEMA DR-4620). Flood event — may have impacted local water infrastructure.

Violation
1 drinking water violation recorded

Contaminants: Fluoride.

Violation
3 drinking water violations recorded

Contaminants: Fluoride, TTHM, Total Haloacetic Acids (HAA5).

Violation
1 drinking water violation recorded

Contaminants: Revised Total Coliform Rule.

Key contaminant findings

Based on the most recent EPA sampling data for Mariano Lake, Pinedale, Churchrock's water supply.

Lead Elevated
Detected: 12.0 ppb Limit: 15 ppb (EPA Action Level)

Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.

PFAS (1 compound) Elevated
Detected: Highest: lithium at 67.0000 µg/L Limit: 0.004 µg/L (EPA MCL)

Detected but within current EPA limits. PFAS do not break down in the environment and can accumulate in the body over time. An activated carbon filter can reduce exposure.

Violation history

Mariano Lake, Pinedale, Churchrock's water system has 35 total violations on record, including 4 health-based violations. 2 remain unresolved. 1 violation was issued in the last 5 years.

MRMONOtherMCL
Most recent violations:
Jan 2021 Fluoride Resolved
Jan 2020 Fluoride Resolved
Jan 2020 TTHM Resolved
Jan 2020 Total Haloacetic Acids (HAA5) Resolved
Apr 2017 Revised Total Coliform Rule Resolved

Flood & environmental risk

Apache 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.

SEVERE STORMS AND FLOODING
Flood FEMA DR-4620
HURRICANE KATRINA EVACUATION
Hurricane FEMA DR-3241
SEVERE STORMS, TORNADOES & FLOODING
Flood FEMA DR-977

Where does Mariano Lake, Pinedale, Churchrock's water come from?

Mariano Lake, Pinedale, Churchrock's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 4,562 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.

What Mariano Lake, Pinedale, Churchrock residents can do

Request your utility's CCR

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.

Flush your taps

Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.

Monitor alerts during storms

Mariano Lake, Pinedale, Churchrock'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.

Contaminant Alerts

Top contaminants to know

View all ↓
Lead (90th percentile)
Inorganic / Heavy Metal
Near Limit
12.0 ppb
EPA Action Level: 15 ppb · 80% of limit
Near LimitFilter: NSF-53
lithium
PFAS / Forever Chemical
Near MCL
67.0000 µg/L
EPA MCL: 0.004 µg/L · +20% over limit
Detected
Lithium
Inorganic
Above state screening
67.0 µg/L
State screening level: 60 µg/L · +12% over limit
DetectedNo federal MCLUCMR 5 Data (2023–2025)
PFAS Testing

Forever chemicals overview

National PFAS report →
30
Compounds tested
1
Detected
0
Exceed EPA MCL
Compliance Record

Violation summary

35
Total violations
4
Health-based
2
Active / unresolved
Jan 2021
Most recent violation
Compliance Record

Violations & advisories

35 Total
2 Active
4 Health-based
33 Resolved
Violations by category
Synthetic Organic Chemicals
8
Total Coliform Rule
7
Volatile Organic Chemicals
7
Revised Total Coliform Rule
5
Stage 2 Disinfectants and Disinfection Byproducts Rule
4
Apr 2016 Active
Revised Total Coliform Rule
Other Violation 0
Active
Compliance Violation
Monitoring 0
Jan 2021 Resolved
Fluoride
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2021
Jan 2020 Resolved
Fluoride
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2020
Jan 2020 Resolved
TTHM
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2020
Jan 2020 Resolved
Total Haloacetic Acids (HAA5)
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2020
Apr 2017 Resolved
Revised Total Coliform Rule
Monitoring
Monitoring Resolved Apr 2017
Mar 2017 Resolved
Revised Total Coliform Rule
Monitoring
Monitoring Resolved Mar 2017
Feb 2017 Resolved
Revised Total Coliform Rule
Monitoring
Monitoring Resolved Feb 2017
Jan 2017 Resolved
Revised Total Coliform Rule
Monitoring
Monitoring Resolved Jan 2017
Jan 2014 Resolved
Total Haloacetic Acids (HAA5)
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2014
Jan 2014 Resolved
TTHM
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2014
Jul 2013 Resolved
Glyphosate
Monitoring & Reporting
Monitoring & Reporting Resolved Sep 2013
Jul 2013 Resolved
Endothall
Monitoring & Reporting
Monitoring & Reporting Resolved Sep 2013
Jul 2013 Resolved
2,3,7,8-TCDD
Monitoring & Reporting
Monitoring & Reporting Resolved Sep 2013
Jul 2013 Resolved
Diquat
Monitoring & Reporting
Monitoring & Reporting Resolved Sep 2013
Dec 2012 Resolved
Coliform (TCR)
Monitoring & Reporting
Monitoring & Reporting Resolved Dec 2012
Nov 2012 Resolved
Coliform (TCR)
Monitoring & Reporting
Monitoring & Reporting Resolved Nov 2012
Feb 2012 Resolved
Coliform (TCR)
Monitoring & Reporting
Monitoring & Reporting Resolved Feb 2012
Oct 2010 Resolved
1,2-DIBROMO-3-CHLOROPROPANE
Max Contaminant Level
Health-Based Health Resolved Dec 2010
Showing 20 of 35 violations
Environmental Risk

Flood & disaster history

6
Declared disasters
Sep 2021
Most recent
Flood
Most common type

Apache 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.

Sep 2021
SEVERE STORMS AND FLOODING
Flood FEMA #4620
Sep 2005
HURRICANE KATRINA EVACUATION
Hurricane FEMA #3241
Jan 1993
SEVERE STORMS, TORNADOES & FLOODING
Flood FEMA #977
Oct 1983
SEVERE STORMS & FLOODING
Flood FEMA #691
Mar 1978
SEVERE STORMS & FLOODING
Flood FEMA #551
Sep 1970
HEAVY RAINS & FLASH
Flood FEMA #294

Recommended water filters

Based on contaminants detected in Mariano Lake, Pinedale, Churchrock's water supply, we recommend the following filter types.

🚰
For Lead
Reverse Osmosis or NSF 53-Certified Pitcher
Lead detected at 12.0 ppb
Read our guide →
🧪
For PFAS
Reverse Osmosis or Activated Carbon Block
1 PFAS compound detected

Full contaminants report

Contaminant Detected Level EPA Limit Unit Category Status
Lead (90th percentile) 12.0 15 ppb Inorganic Near Limit
11Cl-PF3OUdS ND HI µg/L PFAS Not Detected
4:2 FTS ND HI µg/L PFAS Not Detected
6:2 FTS ND HI µg/L PFAS Not Detected
8:2 FTS ND HI µg/L PFAS Not Detected
9Cl-PF3ONS ND HI µg/L PFAS Not Detected
ADONA ND HI µg/L PFAS Not Detected
HFPO-DA ND 0.01 µg/L PFAS Not Detected
lithium 67.000 HI µg/L PFAS Detected
NEtFOSAA ND HI µg/L PFAS Not Detected
NFDHA ND HI µg/L PFAS Not Detected
NMeFOSAA ND HI µg/L PFAS Not Detected
PFBA ND HI µg/L PFAS Not Detected
PFBS ND HI µg/L PFAS Not Detected
PFDA ND HI µg/L PFAS Not Detected
PFDoA ND HI µg/L PFAS Not Detected
PFEESA ND HI µg/L PFAS Not Detected
PFHpA ND HI µg/L PFAS Not Detected
PFHpS ND HI µg/L PFAS Not Detected
PFHxA ND HI µg/L PFAS Not Detected
PFHxS ND HI µg/L PFAS Not Detected
PFMBA ND HI µg/L PFAS Not Detected
PFMPA ND HI µg/L PFAS Not Detected
PFNA ND HI µg/L PFAS Not Detected
PFOA ND 0.004 µg/L PFAS Not Detected
PFOS ND 0.004 µg/L PFAS Not Detected
PFPeA ND HI µg/L PFAS Not Detected
PFPeS ND HI µg/L PFAS Not Detected
PFTA ND HI µg/L PFAS Not Detected
PFTrDA ND HI µg/L PFAS Not Detected
PFUnA ND HI µg/L PFAS Not Detected
Data source: EPA SDWIS, UCMR 5, local utility CCR.

Lead level trend (90th percentile)

EPA action level: 15 ppb
Lead has increased by 11.0 ppb from 1994 (1.0 ppb) to 2022 (12.0 ppb).
Contaminant Rankings

See how Mariano Lake, Pinedale, Churchrock compares by contaminant

Explore where Mariano Lake, Pinedale, Churchrock ranks among all Arizona cities for specific contaminants.

Infrastructure

Water source & infrastructure

Primary Source
Groundwater
Operator
Native American
Population Served
4,562
Water Systems
1
Water Source

Where Mariano Lake, Pinedale, Churchrock's water comes from

Groundwater

Mariano Lake, Pinedale, Churchrock'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 native american ownership and serves approximately 4,562 people through 1 water system.

Infrastructure

Water systems serving Mariano Lake, Pinedale, Churchrock

System Name PWSID Population Source
Mariano Lake-Pinedale-Church Rock NTUA NN3500211 4,562 GW
Regional Comparison

How Mariano Lake, Pinedale, Churchrock compares

Full Arizona rankings →

Mariano Lake, Pinedale, Churchrock's score of 84.5/100 is above the average of 42/100 among major Arizona cities. It outscores 10 of 10 nearby cities.

Mariano Lake, Pinedale, Churchrock (this city)
84.5
Phoenix
37.5
Tucson
38.1
Mesa
40.6
Chandler
40.5
Gilbert
34.8
Arizona avg
42
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Frequently asked questions

Is Mariano Lake, Pinedale, Churchrock, AZ tap water safe to drink?

Mariano Lake, Pinedale, Churchrock's water quality earned a grade of B+ (84.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #89 out of 292 cities tested in Arizona.

What contaminants are in Mariano Lake, Pinedale, Churchrock's water?

Lead was measured at 12.0 ppb (90th percentile). 1 PFAS compound was detected. 35 violations are on record.

How is Mariano Lake, Pinedale, Churchrock'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 Mariano Lake, Pinedale, Churchrock?

While lead levels are within EPA limits, a filter adds extra protection. PFAS compounds have been detected. A filter with activated carbon can help reduce exposure.

Where does Mariano Lake, Pinedale, Churchrock's water come from?

Mariano Lake, Pinedale, Churchrock's water is sourced from Groundwater. The city has 1 water system serving approximately 4,562 residents.

What health violations has Mariano Lake, Pinedale, Churchrock's water system had?

Mariano Lake, Pinedale, Churchrock has 4 health-based violations on record. The most recent violation was recorded in January 2021. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.

Is Mariano Lake, Pinedale, Churchrock's groundwater at risk of contamination?

Mariano Lake, Pinedale, Churchrock 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 35 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 Mariano Lake, Pinedale, Churchrock's water compare to other cities?

Mariano Lake, Pinedale, Churchrock ranks #89 out of 292 cities in Arizona (better than 70% of state cities) and #5849 out of 15744 cities nationally (63th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.