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Tap water quality report

Willow Lake

EPA monitoring tested this supplier for 21 contaminants and detected 8. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

21
contaminants tested
8
detected
255
people served
33
health-based violations
South Dakota rankingsLead in South DakotaPFAS in South Dakota
Water source
GWP
Ownership
Local government
Counties served
Clark

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.

33
health-based violations
43
violations on file
0
still open
ViolationTypeStatusPeriod
TT Health-based Resolved 2020-11-23
TT Health-based Resolved 2020-11-23
TT Health-based Resolved 2015-02-01
TT Health-based Resolved 2015-02-01
TT Health-based Resolved 2011-02-01
TT Health-based Resolved 2011-02-01
TT Health-based Resolved 2006-02-23
TT Health-based Resolved 2006-02-23
MCL Health-based Resolved 2001-07-01 → 2001-07-31
MCL Health-based Resolved 2001-07-01 → 2001-07-31

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
0.0010 mg/L 6.7%
of the EPA limit 0.0150 mg/L
 13/13 LCR 2024
Copper
591.5 µg/L 46%
of the EPA limit 1300 µg/L
worst single sample: 740 µg/L
10/10 SYR4 2012–2015
Lead
7.895 µg/L 53%
of the EPA limit 15 µg/L
worst single sample: 11.9 µg/L
10/10 SYR4 2012–2015
TTHM
14.58 µg/L 18%
of the EPA limit 80 µg/L
worst single sample: 14.6 µg/L
3/3 SYR4 2012–2015
Total Haloacetic Acids (HAA5)
6.445 µg/L 11%
of the EPA limit 60 µg/L
worst single sample: 6.6 µg/L
3/3 SYR4 2012–2015
Arsenic
4 µg/L 40%
of the EPA limit 10 µg/L
 1/1 SYR4 2018
Barium
27.9 µg/L 1.4%
of the EPA limit 2000 µg/L
 1/1 SYR4 2018
Gross Alpha, Excl. Radon And U
1.9 pCi/L 13%
of the EPA limit 15 pCi/L
 1/1 SYR4 2012
13 contaminants tested, none detected
Antimony, TotalBeryllium, TotalCadmiumChromiumCombined Radium (-226 And -228)Combined UraniumFluorideGross Beta Particle ActivityMercuryNitrateNitriteSeleniumThallium, Total

Utility contact

Contact
LUKE ZELINSKI
Phone
6056253631
Email
[email protected]

Frequently asked questions about Willow Lake

Is Willow Lake tap water safe to drink?

EPA monitoring detected 8 contaminants in Willow Lake'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 Willow Lake's water?

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

How many people does Willow Lake serve?

Willow Lake reports serving 255 people in South Dakota, per its EPA record.

Has Willow Lake had any water quality violations?

The EPA has 43 violations on file for Willow Lake, of which 33 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.