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Tap water quality report

Lewiston City of

EPA monitoring tested this supplier for 107 contaminants and detected 24. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

107
contaminants tested
24
detected
15,001
people served
1
health-based violations
Idaho rankingsLead in IdahoPFAS in Idaho
Water source
Surface water
Ownership
Local government
Counties served
Nez Perce

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

1
health-based violations
82
violations on file
4
still open
ViolationTypeStatusPeriod
MCL Health-based Archived 2002-10-01 → 2002-10-31
MR Monitoring Archived 2023-01-01 → 2026-03-11
MR Monitoring Archived 2023-01-01 → 2026-03-11
MR Monitoring Archived 2023-01-01 → 2026-03-11
MR Monitoring Archived 2023-01-01 → 2026-03-11
MR Monitoring Archived 2023-01-01 → 2025-12-31
MR Monitoring Archived 2023-01-01 → 2025-12-31
MR Monitoring Archived 2023-01-01 → 2025-12-31
MR Monitoring Archived 2023-01-01 → 2025-12-31
MR Monitoring Archived 2023-01-01 → 2025-12-31

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
PFBS 0.0056 µg/L 1/14 2025
Pfhxa 0.0043 µg/L 1/14 2025
Pfpea 0.0047 µg/L 1/14 2025

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Nitrate
6814.5 µg/L 68%
of the EPA limit 10000 µg/L
worst single sample: 7190 µg/L
72/104 SYR4 2012–2019
TTHM
51.58 µg/L 64%
of the EPA limit 80 µg/L
worst single sample: 53.1 µg/L
48/64 SYR4 2012–2019
Barium
113 µg/L 5.7%
of the EPA limit 2000 µg/L
worst single sample: 135 µg/L
38/38 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
37.73 µg/L 63%
of the EPA limit 60 µg/L
worst single sample: 47.1 µg/L
38/44 SYR4 2012–2019
Fluoride
929.2 µg/L 23%
of the EPA limit 4000 µg/L
worst single sample: 930 µg/L
37/38 SYR4 2012–2019
Nitrate-Nitrite
6882 µg/L 69%
of the EPA limit 10000 µg/L
worst single sample: 7420 µg/L
32/46 SYR4 2012–2019
Chromium
2.91 µg/L 2.9%
of the EPA limit 100 µg/L
worst single sample: 3.1 µg/L
20/38 SYR4 2012–2019
Lead
0.0010 mg/L 6.7%
of the EPA limit 0.0150 mg/L
 17/17 LCR 2025
Lithium
43.8 µg/L
No EPA limit set
 10/14 UCMR-5 2025
Gross Beta Particle Activity
8.206 pCi/L
No EPA limit set
worst single sample: 8.36 pCi/L
8/8 SYR4 2013–2019
Arsenic
2.149 µg/L 21%
of the EPA limit 10 µg/L
worst single sample: 2.2 µg/L
7/42 SYR4 2012–2019
Combined Radium (-226 And -228)
0.9000 pCi/L 18%
of the EPA limit 5 pCi/L
worst single sample: 1 pCi/L
5/7 SYR4 2012–2017
Selenium
3.364 µg/L 6.7%
of the EPA limit 50 µg/L
worst single sample: 3.52 µg/L
5/38 SYR4 2012–2019
Asbestos
-0.13 MFL -1.8%
of the EPA limit 7 MFL
 4/4 SYR4 2013
Combined Uranium
24.521 µg/L 82%
of the EPA limit 30 µg/L
worst single sample: 28.4 µg/L
4/8 SYR4 2012–2019
Nitrite
374.3 µg/L 37%
of the EPA limit 1000 µg/L
worst single sample: 377 µg/L
3/48 SYR4 2012–2019
Gross Alpha, Excl. Radon And U
7.245 pCi/L 48%
of the EPA limit 15 pCi/L
worst single sample: 7.5 pCi/L
2/4 SYR4 2012–2019
Bromodichloromethane
3.2 µg/L
No EPA limit set
 1/1 SYR4 2019
Cadmium
1.07 µg/L 21%
of the EPA limit 5 µg/L
 1/38 SYR4 2012–2019
Chloroform
6.31 µg/L
No EPA limit set
 1/1 SYR4 2019
Dibromochloromethane
1.15 µg/L
No EPA limit set
 1/1 SYR4 2019
83 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,3,7,8-TCDD2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalBromoformChlorobenzeneCyanideCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorNetfosaaNfdhaNmefosaaOxamylPfbaPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpesPftaPftrdaPfunaPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
LACY, BRYAN
Phone
208-746-7461
Email
[email protected]

Frequently asked questions about Lewiston City of

Is Lewiston City of tap water safe to drink?

EPA monitoring detected 24 contaminants in Lewiston City of's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Lewiston City of's water?

EPA monitoring detected Nitrate, TTHM, Barium, Total Haloacetic Acids (HAA5), Fluoride, and others. The full list with the level and data source for each is above.

How many people does Lewiston City of serve?

Lewiston City of reports serving 15,001 people in Idaho, per its EPA record.

Has Lewiston City of had any water quality violations?

The EPA has 82 violations on file for Lewiston City of, of which 1 is health-based (a contaminant limit or required treatment was breached) and 4 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.