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Tap water quality report

Thornton Water Association

EPA monitoring tested this supplier for 65 contaminants and detected 7. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

65
contaminants tested
7
detected
55
people served
4
health-based violations
Washington rankingsLead in WashingtonPFAS in Washington
Water source
Ground water
Ownership
Private
Counties served
Whatcom

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.

4
health-based violations
17
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Archived 2003-11-01 → 2003-11-30
MCL Health-based Archived 1996-06-01 → 1996-06-30
MCL Health-based Archived 1996-03-01 → 1996-03-31
MCL Health-based Archived 1995-10-01 → 1995-10-31
MON Monitoring Resolved 2025-09-01 → 2025-09-30
MR Monitoring Archived 1995-09-01 → 1995-09-30
MR Monitoring Archived 1992-08-01 → 1992-08-31
MR Monitoring Archived 1992-07-01 → 1992-07-31
MR Monitoring Archived 1979-10-01 → 1979-10-31
MR Monitoring Archived 1979-10-01 → 1979-10-31

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
Lead
0.0025 mg/L 17%
of the EPA limit 0.0150 mg/L
 12/12 LCR 2025
Nitrate
150 µg/L 1.5%
of the EPA limit 10000 µg/L
 2/8 SYR4 2014–2018
Arsenic
1 µg/L 10%
of the EPA limit 10 µg/L
 1/1 SYR4 2018
Barium
32 µg/L 1.6%
of the EPA limit 2000 µg/L
 1/1 SYR4 2018
Chromium
1 µg/L 1%
of the EPA limit 100 µg/L
 1/1 SYR4 2018
Fluoride
320 µg/L 8%
of the EPA limit 4000 µg/L
 1/1 SYR4 2018
Nitrate-Nitrite
150 µg/L 1.5%
of the EPA limit 10000 µg/L
 1/1 SYR4 2018
58 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAntimony, TotalAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalBromodichloromethaneBromoformChlorobenzeneCopperCyanideCadmiumCarbon TetrachlorideChlordaneChloroformDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDibromochloromethaneDinosebEndrinEthylbenzeneGross Beta Particle ActivityHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoLeadMercuryMethoxychlorNitritePentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
Justin Remaklus

Frequently asked questions about Thornton Water Association

Is Thornton Water Association tap water safe to drink?

EPA monitoring detected 7 contaminants in Thornton Water Association'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 Thornton Water Association's water?

EPA monitoring detected Lead, Nitrate, Arsenic, Barium, Chromium, and others. The full list with the level and data source for each is above.

How many people does Thornton Water Association serve?

Thornton Water Association reports serving 55 people in Washington, per its EPA record.

Has Thornton Water Association had any water quality violations?

The EPA has 17 violations on file for Thornton Water Association, of which 4 are health-based (a contaminant limit or required treatment was breached) and 0 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.