Is Eureka, 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 ↓
79.4/100
waterverge.com Eureka, SD — Water Quality Report
Eureka's drinking water received a grade of B (79.4 out of 100), indicating good water quality. The city's 1 water system serves approximately 813 residents using purchased surface water.
Lead levels were measured at 4.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 11 violations on record, including 4 health-based violations. 5 remain unresolved.
What to know about Eureka's water
Eureka ranks #99 out of 141 cities in South Dakota for water quality, placing it below average in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
As a small community water system, Eureka may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Eureka, SD water safe to drink?
Eureka's drinking water has significant quality concerns based on EPA testing data. With a grade of B (79.4/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 813 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Eureka
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Eureka's water quality assessment. Grade: B (79.4/100).
Contaminants: Lead and Copper 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.
1 health-based. Contaminants: Stage 1 Disinfectants and Disinfection Byproducts Rule.
Federal disaster declaration (FEMA DR-1915). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Eureka's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Eureka's water system has 11 total violations on record, including 4 health-based violations. 5 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
McPherson County has experienced 6 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 Eureka's water come from?
Eureka's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 1 water system serving approximately 813 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment.
What Eureka residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Eureka'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.
Eureka'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
Flood & disaster history
McPherson County has experienced 6 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 Eureka'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. | 4.0 | 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. | 2.00 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 1.840 mg/L (1995)
EPA action level: 1.3 mg/L
See how Eureka compares by contaminant
Explore where Eureka ranks among all South Dakota cities for specific contaminants.
Water source & infrastructure
Where Eureka's water comes from
Eureka's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 813 people through 1 water system.
Water systems serving Eureka
| System Name | PWSID | Population | Source |
|---|---|---|---|
| EUREKA | SD4600121 | 813 | SWP |
How Eureka compares
Full South Dakota rankings →Eureka's score of 79.4/100 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 Eureka, SD
Wikipedia →Eureka is a city in western McPherson County, South Dakota, United States, near the North Dakota state line. The population was 813 at the 2020 census.
Learn more about your water
Guides and resources related to Eureka's water quality findings.
Explore water quality across Mcpherson
Frequently asked questions
Is Eureka, SD tap water safe to drink?
Eureka's water quality earned a grade of B (79.4/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #99 out of 141 cities tested in South Dakota.
What contaminants are in Eureka's water?
Lead was measured at 4.0 ppb (90th percentile). 11 violations are on record.
How is Eureka'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 Eureka?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Eureka's water come from?
Eureka's water is sourced from Purchased surface water. The city has 1 water system serving approximately 813 residents.
What health violations has Eureka's water system had?
Eureka has 4 health-based violations on record. The most recent violation was recorded in October 2023. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 5 violations remain unresolved.
How does Eureka's water compare to other cities?
Eureka ranks #99 out of 141 cities in South Dakota (better than 30% of state cities) and #8278 out of 15744 cities nationally (47th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Eureka's small water system affect quality?
Eureka's system serves approximately 813 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 11 violations on record.