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. EPA SDWIS lists this system's service population as 76,960 people using Surface Water sources.

How many people does Flagstaff City Of serve?

EPA SDWIS reports that Flagstaff City Of serves 76,960 people (this public water system's service population, not the municipal population of Flagstaff or any other city). It is a Local-owned system using Surface Water water sources with 23,869 service connections. The operator address is listed in Flagstaff, Arizona.

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.

Where does Flagstaff City Of sit among U.S. public water systems?

According to EPA SDWIS population_served among sitemap-advertised systems (serving 500+), Flagstaff City Of ranks #677 of 29,740 by people served, and #17 of 413 in Arizona. Ordinals use population_served DESC among systems serving 500+ (the sitemap cohort). See /methodology#corpus-placement.

How does Flagstaff City Of's violation count compare nationally?

Flagstaff City Of has 1,061 recorded EPA SDWIS violations, fewer than 1% of the 29,740 public water systems serving 500 or more people nationwide (the same sitemap cohort used for the corpus-placement ranking above). 99% of that cohort has fewer violations than Flagstaff City Of. A system can have zero recorded violations and still be actively monitored, and a high violation count often reflects a system that reports thoroughly, not necessarily one with worse water.

States → Arizona

Community Water System · PWS AZ0403008

Flagstaff City Of

Operator location Flagstaff, Arizona - UCMR5 detected 1 PFAS compound (lower-third PFAS panel (≤ 2 compounds)) on this PWS; SDWIS lists 1,061 violations and 76,960 people served.

Compiled by PlainWater · May 15, 2026

76,960
People served (this PWS) Larger third of systems: 1,061
EPA violations (this PWS) Upper third of systems: 7
Health-based (this PWS) Middle third by health-based share: 1 PFAS
UCMR5 (this PWS) Lower third of PFAS-detected systems

Follow published updates (RSS)

Flagstaff City Of standing, high SDWIS violation third

UCMR5 detected 1 PFAS compound - lower-third PFAS panel (≤ 2 compounds). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 1% is middle-third health share (≤ 23%). UCMR5: lower-third PFAS panel (≤ 2 compounds). Population rank #677 of 29,740 among systems serving 500+.

The verdict

Flagstaff City Of sits in the upper third of the sitemap cohort by violation count (1,061), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is large (76,960; larger served population (> 3,309)), so household exposure scale sits behind the violation mix. Health-based share is 1% (middle-third health share (≤ 23%)). UCMR5 detected 1 PFAS compound (lower-third PFAS panel (≤ 2 compounds)).

#677 of 29,740
Population · /systems: #17 of 413
Population · AZ: 1,061
Total EPA violations on record: 1%
Health-based (MCL / treatment failure)

Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.

PFAS Detected

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

Water Safety Score

34/100

Flagstaff City Of

Based on EPA SDWIS violation history and UCMR5 PFAS testing only, not water taste, odor, infrastructure age, or contaminants outside the federally tracked set.

Health-based violations F

EPA SDWIS health-based violations on record (MCL, MRDL, treatment technique)

Monitoring & reporting violations F

1,054

Non-health SDWIS violations (monitoring, reporting, and other compliance)

PFAS contamination B

0.0061 µg/L

Highest PFAS compound level detected in UCMR5 testing

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

Violation Count vs. the National Corpus

Flagstaff City Of has 1,061 recorded EPA violations, 99% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 1% carry more. 1% of this system's own violations are health-based (7 of 1,061), and it ranks #677 of 29,740 by population served among that same cohort.

EPA violations vs. the national water-system corpus

Public water systems serving 500+ people (EPA SDWIS)

1,061 Higher than most more violations than 99% of 29,740 water systems

the national water-system corpus, bucketed by value

Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source EPA SDWIS · 2026-05-15

How many violations vs. how serious, among peer systems

Flagstaff City Of plotted against 29 peer public water systems (500+ people served), by total violation count (x) and the share of those violations that are health-based (y). The crosshair sits at this sample's own median on each axis. A high violation count does not automatically mean a serious record: most monitoring and reporting violations are minor, not health-based.

30 public water systems (500+ people served), EPA SDWIS current release.

How to read this

Each dot is one public water system; the highlighted dot is Flagstaff City Of. A system to the right has more recorded violations; a system higher up has a larger share of those violations classified health-based rather than monitoring or reporting.

Rare but serious: few violations, but most of them are health-based.
Frequent, mostly paperwork: many violations, but mostly monitoring or reporting, not health-based.
Clean record: below-median on both counts, the tinted corner.

View all 30 systems as a list

City of Ballinger: 372 violations, 85% health-based
Nooksack Valley Water Association: 16 violations, 31% health-based
Montgomery Co RWD 12: 7 violations, 29% health-based
Irvin Water District #6: 11 violations, 27% health-based
Ticonderoga WD: 47 violations, 26% health-based
Pine Valley Plantation: 37 violations, 24% health-based
McLouth, City Of: 29 violations, 17% health-based
Kipling Oaks 1: 25 violations, 16% health-based
South Deerfield Water Supply District: 96 violations, 16% health-based
Sunset Ridge Water District: 82 violations, 15% health-based
Orange Water Dept: 136 violations, 14% health-based
Mount Pleasant Water Sys #1: 167 violations, 11% health-based
Lake Gibson Estates: 42 violations, 2% health-based
Benson Culinary Improvement District: 212 violations, 1% health-based
Conemaugh Twp Muni Auth: 567 violations, 1% health-based
Flagstaff City Of: 1,061 violations, 1% health-based (this system)
Miccosukee Service Plaza: 0 violations, 0% health-based
Brazoria - Fort Bend Counties MUD 3: 0 violations, 0% health-based
Tanglewilde Thompson Place 600: 2 violations, 0% health-based
Center Water Co: 5 violations, 0% health-based
Spring Mills Elem School/Hvs: 9 violations, 0% health-based
Great Bend Industrial Park: 14 violations, 0% health-based
Glen Park Village: 19 violations, 0% health-based
Camp Is-Sho-Da: 22 violations, 0% health-based
Hamilton: 33 violations, 0% health-based
Town of Welaka: 54 violations, 0% health-based
Township of Blairstown Dpw: 61 violations, 0% health-based
McIntosh Water & Fire Pro Authority: 71 violations, 0% health-based
Clarkdale Municipal Water System: 114 violations, 0% health-based
Eureka Water Association: 273 violations, 0% health-based

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

UCMR5 PFAS record for Flagstaff City Of

Open EPA SDWIS federal reports for PWS AZ0403008 to cross-check UCMR5 detections and violation codes; state primacy agencies enforce the Safe Drinking Water Act locally.

EPA SDWIS · PWS AZ0403008 AZ primacy agency

Sources: EPA SDWIS · Arizona DEQ, Drinking Water Program

Nationwide peers

1,061 violations · 76,960 served: nearest cross-state SDWIS matches.

Cross-state systems with comparable violation load

Nearest cross-state community systems (500+ served) by total SDWIS violations on record.

4 peers

Cross-state systems with similar served population

Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).

4 peers

What to do with Flagstaff City Of

Use this system's EPA-reported record as a starting filter, not a final verdict.

See how every tracked system in Arizona compares on the same EPA violation measures. Arizona systems
Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
Find and compare another public water system by name or PWSID. Search systems

EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.

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

Compiled by PlainWater, Drinking Water Quality Editorial Process · May 15, 2026

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