Is Fort Thompson, SD Tap Water Safe to Drink?
Graded C, with 16 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
64.8/100
waterverge.com Fort Thompson, SD — Water Quality Report
Fort Thompson's drinking water received a grade of C (64.8 out of 100), indicating fair water quality. The city's 3 water systems serve approximately 1,567 residents using surface water.
Lead levels were measured at 0.2 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 351 violations on record, including 17 health-based violations. 16 remain unresolved.
What to know about Fort Thompson's water
Fort Thompson ranks #122 out of 141 cities in South Dakota for water quality, placing it among the lowest-rated 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, Fort Thompson may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 13 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Fort Thompson, SD water safe to drink?
Fort Thompson's drinking water has significant quality concerns based on EPA testing data. With a grade of C (64.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 1,567 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Fort Thompson
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Fort Thompson's water quality assessment. Grade: C (64.8/100).
Contaminants: Nitrate-Nitrite.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4807). Flood event — may have impacted local water infrastructure.
Contaminants: Total Haloacetic Acids (HAA5), TTHM.
Federal disaster declaration (FEMA DR-4440). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Fort Thompson's water supply.
Well within EPA limits.
Violation history
Fort Thompson's water system has 351 total violations on record, including 17 health-based violations. 16 remain unresolved. 13 violations were issued in the last 5 years.
Flood & environmental risk
Buffalo County has experienced 9 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. Local water sources include Campbell C Nr Lee'S Corner.
Where does Fort Thompson's water come from?
Fort Thompson's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 3 water systems serving approximately 1,567 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Campbell C Nr Lee'S Corner (river).
What Fort Thompson residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Fort Thompson'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.
Fort Thompson'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
Buffalo County has experienced 9 federally declared disasters since 1969. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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. | 0.2 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Fort Thompson compares by contaminant
Explore where Fort Thompson ranks among all South Dakota cities for specific contaminants.
Water source & infrastructure
Where Fort Thompson's water comes from
Fort Thompson'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 native american ownership and serves approximately 1,567 people through 3 water systems.
Water bodies near Fort Thompson
Fort Thompson is located near 1 notable water body. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Fort Thompson
| System Name | PWSID | Population | Source |
|---|---|---|---|
| FORT THOMPSON WATER SYSTEM | 084690440 | 1,357 | SW |
| CROW CREEK SIOUX TRIBE WATER SYSTEM | 084690439 | 130 | SWP |
| BIG BEND WATER SYSTEM | 084690438 | 80 | GW |
How Fort Thompson compares
Full South Dakota rankings →Fort Thompson's score of 64.8/100 is on par with the average of 66/100 among major South Dakota cities. It outscores 5 of 10 nearby cities.
Nearby cities
View South Dakota rankings →ZIP codes served by Fort Thompson
The water systems serving Fort Thompson cover 1 ZIP code. Select any ZIP to see which water systems serve that area.
About Fort Thompson, SD
Wikipedia →Fort Thompson is a census-designated place (CDP) in Buffalo County, South Dakota, United States. The population was 1,282 at the 2010 census, making it the largest settlement on the Crow Creek Reservation.
Learn more about your water
Guides and resources related to Fort Thompson's water quality findings.
Frequently asked questions
Is Fort Thompson, SD tap water safe to drink?
Fort Thompson's water quality earned a grade of C (64.8/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #122 out of 141 cities tested in South Dakota.
What contaminants are in Fort Thompson's water?
Lead was measured at 0.2 ppb (90th percentile). 351 violations are on record.
How is Fort Thompson'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 Fort Thompson?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Fort Thompson's water come from?
Fort Thompson's water is sourced from Surface water. The city has 3 water systems serving approximately 1,567 residents.
What health violations has Fort Thompson's water system had?
Fort Thompson has 17 health-based violations on record. The most recent violation was recorded in January 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 16 violations remain unresolved.
How does Fort Thompson's water compare to other cities?
Fort Thompson ranks #122 out of 141 cities in South Dakota (better than 13% of state cities) and #11619 out of 15744 cities nationally (26th percentile). The grade of C reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.