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Lake Preston, SD Tap Water Quality 2026

Water quality report for Lake Preston, SD — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at Lake Preston's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Lake Preston PWSID: SD4600398 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 7.00 ppb, 47% of the action level and no violations are open. PFAS has never been sampled at this system.

C

Lake Preston earns a C for water quality

Graded on violations and lead, with state inspection findings. PFAS not tested.

Lead: 7.00 ppb — 47% of the federal action level
PFAS never sampled at this system
4 violations since 2015, 1 health-based
No violations currently open
Lake Preston's lead level vs. all South Dakota community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 7.00 ppb — 47% of the federal action level
✓ Lower lead than 6% of South Dakota utilities
Population Served
585
~332 connections
Water Source
Groundwater
Purchased groundwater from another system — SDWIS source code GWP
Active Violations
0
4 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
47% of EPA action level
7.00 ppb
Action level: 15 ppb
Copper (Cu)
90th percentile of tap samples. SDWIS reports a copper figure only when a system exceeds the action level, so any value here is an exceedance.
138.5% of EPA action level
1,800 ppb
Action level: 1,300 ppb
The 90th-percentile lead result is 7.00 ppb, 47% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home. Copper reached the action level here; a copper figure appears in SDWIS only when a system triggers it.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Revised Total Coliform Rule MONITORING FAILURE — — 2020 Resolved
Chlorine MONITORING AND REPORTING — 4.0 mg/L 2020 Resolved
Groundwater Rule OTHER — — 2019 Resolved
Stage 1 Disinfectants and Disinfection Byproducts Rule TREATMENT TECHNIQUE — — 2017 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

4 violations are on record since 2015, of which 1 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Lake Preston
PWSID SD4600398
Water source Groundwater — Purchased groundwater from another system — SDWIS source code GWP
Population served 585
Service connections 332
Systems serving this area 2
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Lake Preston tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 7.00 ppb, 47% of the action level.
Does Lake Preston water have PFAS? ▼
This system has never been sampled for PFAS. EPA's national monitoring covered systems serving 3,300 people or more, so no results exist — which is not evidence that none is present.
Who supplies water to Lake Preston? ▼
Lake Preston (PWSID SD4600398), one of 2 systems serving this area. Groundwater. Purchased groundwater from another system — SDWIS source code GWP
When was this system last inspected? ▼
It was last inspected on 2024-10-23. No significant deficiencies were recorded.

What Should Lake Preston Residents Do?

1
Consider a filter certified for lead
Look for NSF/ANSI 53 certification for lead reduction.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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