PlainWater
States → Arizona

Community Water System · PWS AZ0403008

Flagstaff City Of

Flagstaff, Arizona 86004 - drinking water served from surface water sources to 76,960 people, tracked in EPA SDWIS and UCMR5.

76,960
People served
1,061
EPA violations
7
Health-based
1 PFAS
UCMR5 result

The verdict

EPA records 1,061 drinking-water violations at Flagstaff City Of, 1% of them health-based - above the Arizona per-system average, and UCMR5 testing detected 1 PFAS compound.

1,061
Total EPA violations on record
1%
Health-based (MCL / treatment failure)
76,960
People served by this system
1
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Flagstaff City Of

Flagstaff City Of is a local-owned community water system that delivers drinking water to 76,960 residents in Flagstaff, Arizona (Coconino County) through 23,869 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 1,061 total violations for this system , of which 7 (1%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 1,017 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Nitrate, recorded in 36 violations (MR). Under EPA's UCMR5 PFAS monitoring program, 1 PFAS compound was detected in samples collected from this system, with a maximum reported concentration of 6.1 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.

Across Arizona, EPA tracks 1,493 public water systems serving 7,322,166 people, with 228,944 cumulative violations and 15,663 health-based violations on record. About 98% of systems in the state carry at least one violation, and state-wide the average per system is 153.3 violations. Statewide, 145 of 152 UCMR5-tested systems have reported PFAS detections (95.4%).

Flagstaff City Of's 1,061 violations sit above the Arizona average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

PFAS Detected

1 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.

Population Served
76,960
Total Violations
1,061
Health-Based Violations
7
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
23,869
County
Coconino
School/Daycare
No
MCL Violations
3
Monitoring Violations
1,017
Treatment Tech Violations
4

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Nitrate MR 36 2011
DICHLOROMETHANE MR 20 2024
Chlorine MR 19 2015
cis-1,2-Dichloroethylene MR 18 2023
o-Dichlorobenzene MR 18 2023
Tetrachloroethylene MR 18 2023
Styrene MR 18 2023
trans-1,2-Dichloroethylene MR 18 2023
1,1,2-Trichloroethane MR 18 2023
Toluene MR 18 2023
Ethylbenzene MR 18 2023
1,2-Dichloropropane MR 18 2023
1,2-DIBROMO-3-CHLOROPROPANE MR 18 2021
ETHYLENE DIBROMIDE MR 18 2021
CHLOROBENZENE MR 18 2023
Xylenes, Total MR 17 2023
p-Dichlorobenzene MR 17 2023
1,2-Dichloroethane MR 17 2023
1,1,1-Trichloroethane MR 17 2023
Carbon tetrachloride MR 17 2023
Trichloroethylene MR 17 2023
Benzene MR 17 2023
1,1-Dichloroethylene MR 17 2023
1,2,4-Trichlorobenzene MR 17 2023
Methoxychlor MR 17 2021
Toxaphene MR 17 2021
2,4-D MR 17 2021
BHC-GAMMA MR 17 2021
Chlordane MR 17 2021
Vinyl chloride MR 16 2023

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 1 of 696 samples detected PFAS.

Contaminant Date Result MRL Status
PFUnA 9/26/2023 <2.00 ppt 2.00 ppt Not Detected
PFHxA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFDA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
11Cl-PF3OUdS 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
PFNA 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFOA 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFHxS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFTA 9/26/2023 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 9/26/2023 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 9/26/2023 <6.00 ppt 6.00 ppt Not Detected
PFHpA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFOS 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFPeS 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFBS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 9/26/2023 <2.00 ppt 2.00 ppt Not Detected
NFDHA 9/26/2023 <20.00 ppt 20.00 ppt Not Detected
PFEESA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFMPA 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
4:2 FTS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
ADONA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
NEtFOSAA 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
PFDA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
NMeFOSAA 9/26/2023 <6.00 ppt 6.00 ppt Not Detected
PFTrDA 9/26/2023 <7.00 ppt 7.00 ppt Not Detected
ADONA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFTA 9/26/2023 <8.00 ppt 8.00 ppt Not Detected
PFBS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFNA 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFOA 9/26/2023 <4.00 ppt 4.00 ppt Not Detected
PFDoA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
PFUnA 9/26/2023 <2.00 ppt 2.00 ppt Not Detected
PFHxA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 9/26/2023 <2.00 ppt 2.00 ppt Not Detected
PFMBA 9/26/2023 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 9/26/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 9/26/2023 <3.00 ppt 3.00 ppt Not Detected

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Flagstaff City Of.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID AZ0403008 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Arizona Drinking Water Authority

Arizona DEQ, Drinking Water Program is the primacy agency that licenses and inspects Flagstaff City Of under EPA-delegated authority.

Open AZ regulator portal

Source: Arizona DEQ, Drinking Water Program

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2025 Surface Water Treatment Rule MR 4 SDWIS / AZ0403008 / 0200
2025 Revised Total Coliform Rule RPT 2 SDWIS / AZ0403008 / 8000
2024 DICHLOROMETHANE MR 20 SDWIS / AZ0403008 / 2964
2023 cis-1,2-Dichloroethylene MR 18 SDWIS / AZ0403008 / 2380
2023 o-Dichlorobenzene MR 18 SDWIS / AZ0403008 / 2968
2023 Tetrachloroethylene MR 18 SDWIS / AZ0403008 / 2987
2023 Styrene MR 18 SDWIS / AZ0403008 / 2996
2023 trans-1,2-Dichloroethylene MR 18 SDWIS / AZ0403008 / 2979
2023 1,1,2-Trichloroethane MR 18 SDWIS / AZ0403008 / 2985
2023 Toluene MR 18 SDWIS / AZ0403008 / 2991
2023 Ethylbenzene MR 18 SDWIS / AZ0403008 / 2992
2023 1,2-Dichloropropane MR 18 SDWIS / AZ0403008 / 2983
2023 CHLOROBENZENE MR 18 SDWIS / AZ0403008 / 2989
2023 Xylenes, Total MR 17 SDWIS / AZ0403008 / 2955
2023 p-Dichlorobenzene MR 17 SDWIS / AZ0403008 / 2969

How Flagstaff City Of Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Flagstaff City Of Arizona avg Federal benchmark
Total violations 1,061 153.3 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 7 10.5 Indicates a contaminant exceeded a federal MCL
PFAS detection 1 compound 95.4% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 76,960 4,904 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,493 regulated public water systems in Arizona.

Federal MCL reference, Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Flagstaff City Of water safe to drink? ▼
Flagstaff City Of (PWS ID: AZ0403008) has 1061 recorded violations in the EPA SDWIS database. PFAS contamination has been detected in UCMR5 testing, with 1 PFAS compound found. This system serves 76,960 people using Surface Water sources.
How many people does Flagstaff City Of serve? ▼
Flagstaff City Of serves 76,960 people in Flagstaff, Arizona. It is a Local-owned system using Surface Water water sources with 23,869 service connections.
What type of violations does Flagstaff City Of have? ▼
Flagstaff City Of has 1,061 total violations: 7 health-based violations (MCL exceedances or treatment failures), 1,017 monitoring/reporting violations, and 4 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Flagstaff City Of water? ▼
Yes. UCMR5 testing detected 1 PFAS compound in Flagstaff City Of's water supply: PFBA. PFAS are persistent "forever chemicals" that do not break down in the environment.
What water source does Flagstaff City Of use? ▼
Flagstaff City Of uses Surface Water as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.