Is Lake Preston, SD Tap Water Safe to Drink?
Graded B — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
78.8/100
waterverge.com Lake Preston, SD — Water Quality Report
Lake Preston's drinking water received a grade of B (78.8 out of 100), indicating good water quality. The city's 1 water system serves approximately 589 residents using purchased ground water.
Lead levels were measured at 7.0 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 17 violations on record, including 4 health-based violations. 8 remain unresolved.
What to know about Lake Preston's water
Lake Preston ranks #106 out of 141 cities in South Dakota for water quality, placing it below average in the state.
Lake Preston purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
As a small community water system, Lake Preston may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Lake Preston, SD water safe to drink?
Lake Preston's drinking water has significant quality concerns based on EPA testing data. With a grade of B (78.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 589 residents using groundwater (wells).
Recent water quality updates for Lake Preston
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Lake Preston's water quality assessment. Grade: B (78.8/100).
Contaminants: Revised Total Coliform Rule, Chlorine.
Contaminants: Groundwater Rule.
Federal disaster declaration (FEMA DR-4440). Flood event — may have impacted local water infrastructure.
1 health-based. Contaminants: Stage 1 Disinfectants and Disinfection Byproducts Rule.
Federal disaster declaration (FEMA DR-1984). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Lake Preston's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Lake Preston's water system has 17 total violations on record, including 4 health-based violations. 8 remain unresolved.
Flood & environmental risk
Kingsbury County has experienced 10 federally declared disasters since 1969. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Lake Preston's water come from?
Lake Preston's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 589 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Lake Preston residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Lake Preston's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Lake Preston's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D1 — moderate droughtKingsbury County is currently in D1 (moderate drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Kingsbury County has experienced 10 federally declared disasters since 1969. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Lake Preston's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 7.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.80 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 1.800 mg/L (1993)
EPA action level: 1.3 mg/L
See how Lake Preston compares by contaminant
Explore where Lake Preston ranks among all South Dakota cities for specific contaminants.
Water source & infrastructure
Where Lake Preston's water comes from
Lake Preston purchases its water supply from a regional wholesale provider rather than treating raw water directly.
Water quality depends on both the wholesaler's treatment standards and the condition of Lake Preston's local distribution pipes and storage facilities.
Purchased water systems are common in suburban areas and smaller communities that lack the infrastructure for independent treatment.
The system is operated by local government ownership and serves approximately 589 people through 1 water system.
Water systems serving Lake Preston
| System Name | PWSID | Population | Source |
|---|---|---|---|
| LAKE PRESTON | SD4600398 | 589 | GWP |
How Lake Preston compares
Full South Dakota rankings →Lake Preston's score of 78.8/100 is above the average of 66/100 among major South Dakota cities. It outscores 6 of 10 nearby cities.
Nearby cities
View South Dakota rankings →About Lake Preston, SD
Wikipedia →Lake Preston is a city in Kingsbury County, South Dakota, United States. As of the 2020 census, Lake Preston had a population of 589.
Learn more about your water
Guides and resources related to Lake Preston's water quality findings.
Explore water quality across Kingsbury
Frequently asked questions
Is Lake Preston, SD tap water safe to drink?
Lake Preston's water quality earned a grade of B (78.8/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #106 out of 141 cities tested in South Dakota.
What contaminants are in Lake Preston's water?
Lead was measured at 7.0 ppb (90th percentile). 17 violations are on record.
How is Lake Preston's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Lake Preston?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Lake Preston's water come from?
Lake Preston's water is sourced from Purchased ground water. The city has 1 water system serving approximately 589 residents.
What health violations has Lake Preston's water system had?
Lake Preston has 4 health-based violations on record. The most recent violation was recorded in April 2020. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 8 violations remain unresolved.
Is Lake Preston's groundwater at risk of contamination?
Lake Preston uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 17 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Lake Preston's water compare to other cities?
Lake Preston ranks #106 out of 141 cities in South Dakota (better than 25% of state cities) and #8523 out of 15744 cities nationally (46th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Lake Preston's small water system affect quality?
Lake Preston's system serves approximately 589 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 17 violations on record.