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Tap water quality report

Williston City of

EPA monitoring tested this supplier for 95 contaminants and detected 22. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

95
contaminants tested
22
detected
26,426
people served
29
health-based violations
North Dakota rankingsLead in North DakotaPFAS in North Dakota
Water source
Surface water
Ownership
Local government
Counties served
Williams

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.

29
health-based violations
40
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2014-06-01 → 2014-06-30
TT Health-based Resolved 2014-06-01 → 2014-06-30
TT Health-based Resolved 2014-06-01 → 2014-06-30
TT Health-based Resolved 2014-06-01 → 2014-06-30
TT Health-based Resolved 2011-02-01 → 2011-02-28
TT Health-based Resolved 2011-02-01 → 2011-02-28
TT Health-based Resolved 2011-02-01 → 2011-02-28
TT Health-based Resolved 2011-02-01 → 2011-02-28
MCL Health-based Resolved 2006-01-01 → 2006-03-31
MCL Health-based Resolved 2006-01-01 → 2006-03-31

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
Bromodichloromethane
8.007 µg/L
No EPA limit set
worst single sample: 10.09 µg/L
128/128 SYR4 2012–2019
Chloroform
27.1275 µg/L
No EPA limit set
worst single sample: 32.34 µg/L
128/128 SYR4 2012–2019
TTHM
36.2665 µg/L 45%
of the EPA limit 80 µg/L
worst single sample: 40.78 µg/L
128/128 SYR4 2012–2019
Dichloroacetic Acid
14.32 µg/L
No EPA limit set
worst single sample: 17 µg/L
127/128 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
17.274 µg/L 29%
of the EPA limit 60 µg/L
worst single sample: 22.24 µg/L
127/128 SYR4 2012–2019
Dibromochloromethane
2.4855 µg/L
No EPA limit set
worst single sample: 3.18 µg/L
124/128 SYR4 2012–2019
Trichloroacetic Acid
3.853 µg/L
No EPA limit set
worst single sample: 5.24 µg/L
115/128 SYR4 2012–2019
Copper
49.92 µg/L 3.8%
of the EPA limit 1300 µg/L
worst single sample: 64.6 µg/L
29/60 SYR4 2014–2017
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 15/15 LCR 2023
Nitrate-Nitrite
300 µg/L 3%
of the EPA limit 10000 µg/L
 12/16 SYR4 2012–2019
Lead
3.037 µg/L 20%
of the EPA limit 15 µg/L
worst single sample: 3.46 µg/L
7/60 SYR4 2014–2017
Dibromoacetic Acid
1.1325 µg/L
No EPA limit set
worst single sample: 1.14 µg/L
6/128 SYR4 2012–2019
Lithium
79 µg/L
No EPA limit set
 4/4 UCMR-5 2023
Monochloroacetic Acid
2.444 µg/L
No EPA limit set
worst single sample: 2.46 µg/L
2/128 SYR4 2012–2019
Barium
14.3 µg/L 0.7%
of the EPA limit 2000 µg/L
 1/1 SYR4 2016
Chromium
1.17 µg/L 1.2%
of the EPA limit 100 µg/L
 1/1 SYR4 2016
Combined Radium (-226 And -228)
0.7800 pCi/L 16%
of the EPA limit 5 pCi/L
 1/1 SYR4 2017
Combined Uranium
-0.44 µg/L -1.5%
of the EPA limit 30 µg/L
 1/1 SYR4 2017
Fluoride
810 µg/L 20%
of the EPA limit 4000 µg/L
 1/1 SYR4 2016
Gross Alpha, Excl. Radon And U
3.9 pCi/L 26%
of the EPA limit 15 pCi/L
 1/1 SYR4 2017
Pentachlorophenol
0.0300 µg/L 3%
of the EPA limit 1 µg/L
 1/1 SYR4 2017
Selenium
1.44 µg/L 2.9%
of the EPA limit 50 µg/L
 1/1 SYR4 2016
73 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalArsenicAtrazineBhc-GammaBenzeneBeryllium, TotalBromoformChlorobenzeneCadmiumCarbon TetrachlorideChlordaneDichloromethaneDalaponDinosebEndrinEthylbenzeneHfpo-DaHeptachlorHeptachlor EpoxideLassoMercuryMethoxychlorMonobromoacetic AcidNetfosaaNfdhaNmefosaaPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPicloramSimazineStyreneTetrachloroethyleneThallium, TotalTolueneToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
CLARYS, CURTIS
Phone
701-557-7104
Email
[email protected]

Frequently asked questions about Williston City of

Is Williston City of tap water safe to drink?

EPA monitoring detected 22 contaminants in Williston 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 Williston City of's water?

EPA monitoring detected Bromodichloromethane, Chloroform, TTHM, Dichloroacetic Acid, Total Haloacetic Acids (HAA5), and others. The full list with the level and data source for each is above.

How many people does Williston City of serve?

Williston City of reports serving 26,426 people in North Dakota, per its EPA record.

Has Williston City of had any water quality violations?

The EPA has 40 violations on file for Williston City of, of which 29 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.