Tap Water Quality Report
Tap water quality in FLAGSTAFF, Arizona
Tap water in FLAGSTAFF, Arizona receives a grade of D (67/100) from TapWaterSafety.org. It's served by FLAGSTAFF CITY OF. The most significant water quality concerns are: Arsenic significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in FLAGSTAFF's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving FLAGSTAFF.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 8.2 ppb, 2050x above the EWG health guideline of 0.004 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 19.2 ppb, 320x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 17.3 ppb, 115x above the EWG health guideline of 0.15 ppb.
EPA compliance record
Official U.S. EPA records for FLAGSTAFF CITY OF (system ID AZ0403008) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Volatile Organic Chemicals | Missed testing or reporting | 01/01/2023 | Open |
| Revised Total Coliform Rule | Missed reporting | 07/01/2025 | Open |
| Synthetic Organic Chemicals | Missed testing or reporting | 01/01/2021 | Open |
| Surface Water Treatment Rule | Missed testing or reporting | 06/01/2025 | Open |
| Stage 1 Disinfectants and Disinfection Byproducts Rule | Missed testing or reporting | 04/01/2023 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for FLAGSTAFF
Filters matched to the specific contaminants in FLAGSTAFF's water supply.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in FLAGSTAFF's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Arsenic Heavy metal |
8.2 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 2050× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
19.2 ppb | 0.06 | — | — | — | — | — | 320× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
17.3 ppb | 0.15 | 80.0 | 100 | — | — | — | 115× over |
| Chromium (hexavalent) Heavy metal |
1.31 ppb | 0.02 | — | — | — | — | — | 66× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
6.17 ppb | 0.1 | 60.0 | 60 | — | — | — | 62× over |
| Radium, combined (-226 and -228) Radiological |
0.37 pCi/L | 0.05 | 5.0 | — | — | — | — | 7.4× over |
| Nitrate Inorganic |
0.589 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 4.2× over |
| Nitrate and nitrite Inorganic |
0.342 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.4× over |
| Chlorite Disinfection byproduct |
69.0 ppb | 50.0 | 1000.0 | — | — | — | — | 1.4× over |
| Uranium Radiological |
0.56 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 1.3× over |
| Barium Heavy metal |
180.0 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Vanadium Other |
1.97 ppb | 21.0 | — | — | — | — | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.0236 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Chlorate Disinfection byproduct |
2.14 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.355 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
0.339 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.0661 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.065 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from FLAGSTAFF CITY OF.