Is Clark, SD Tap Water Safe to Drink?
Graded A- — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
87.4/100
waterverge.com Clark, SD — Water Quality Report
Clark's drinking water received a grade of A- (87.4 out of 100), indicating good water quality. The city's 3 water systems serve approximately 4,075 residents using groundwater.
Lead levels were measured at 0.0 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 85 violations on record, including 2 health-based violations. 3 remain unresolved.
What to know about Clark's water
Clark ranks #58 out of 141 cities in South Dakota for water quality, placing it mid-range in the state.
Clark relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
Water quality score
See methodology →Is Clark, SD water safe to drink?
Clark's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (87.4/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 4,075 residents using groundwater (wells).
Recent water quality updates for Clark
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Clark's water quality assessment. Grade: A- (87.4/100).
Federal disaster declaration (FEMA DR-4718). Flood event — may have impacted local water infrastructure.
Contaminants: Nitrate.
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.
Key contaminant findings
Based on the most recent EPA sampling data for Clark'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
Clark's water system has 85 total violations on record, including 2 health-based violations. 3 remain unresolved.
Flood & environmental risk
Clark County has experienced 10 federally declared disasters since 1986. 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 Clark's water come from?
Clark's drinking water comes from groundwater (wells), supplied by 3 water systems serving approximately 4,075 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Clark residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Clark'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.
Clark'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
Clark County has experienced 10 federally declared disasters since 1986. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Clark'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. | 0.0 | 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. | 1.40 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 1.400 mg/L (2022)
EPA action level: 1.3 mg/L
See how Clark compares by contaminant
Explore where Clark ranks among all South Dakota cities for specific contaminants.
Water source & infrastructure
Where Clark's water comes from
Clark's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 4,075 people through 3 water systems.
Water systems serving Clark
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CLARK RURAL WATER SYSTEM | SD4600881 | 2,325 | GW |
| CLARK | SD4600091 | 1,148 | GWP |
| CLARK RURAL WATER-KAMPESKA | SD4602277 | 602 | GW |
How Clark compares
Full South Dakota rankings →Clark's score of 87.4/100 is above the average of 66/100 among major South Dakota cities. It outscores 7 of 10 nearby cities.
Nearby cities
View South Dakota rankings →About Clark, SD
Wikipedia →Clark is a city in and county seat of Clark County, South Dakota, United States. The population was 1,148 at the 2020 census.
Learn more about your water
Guides and resources related to Clark's water quality findings.
Explore water quality across Clark
Frequently asked questions
Is Clark, SD tap water safe to drink?
Clark's water quality earned a grade of A- (87.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #58 out of 141 cities tested in South Dakota.
What contaminants are in Clark's water?
Lead was measured at 0.0 ppb (90th percentile). 85 violations are on record.
How is Clark'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 Clark?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Clark's water come from?
Clark's water is sourced from Groundwater. The city has 3 water systems serving approximately 4,075 residents.
What health violations has Clark's water system had?
Clark has 2 health-based violations on record. The most recent violation was recorded in July 2019. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 3 violations remain unresolved.
Is Clark's groundwater at risk of contamination?
Clark 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 85 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 Clark's water compare to other cities?
Clark ranks #58 out of 141 cities in South Dakota (better than 59% of state cities) and #4065 out of 15744 cities nationally (74th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.