Water Service Outages in South Dakota by City

South Dakota drinking water record

• Community water systems: 463 active systems serve about 879,933 people. 418 of them (90%) serve 3,300 people or fewer; 325 draw mainly on groundwater and 136 on surface water.
• Health-based violations since 2015: 482, at 186 systems (40% of all systems). That share is 39th of 50 states (1 = lowest).
• Most common problems: uncertified operators (210); contaminant averages over the limit (196); uncorrected Ground Water Rule deficiencies (39). Source: EPA SDWIS
• Largest system: Sioux Falls, about 216,462 people, with 0 health-based violations since 2015. Source: EPA SDWIS
• Housing age: the median South Dakota home was built in 1980 (US 1980). Source: US Census Bureau, ACS 2020–2024 (table B25035)
• Storm damage to water service: NOAA storm narratives mention water mains, boil water notices or lost water service in 4 episodes in South Dakota since 2015. Source: NOAA Storm Events Database
• June 21, 2024, Clay (flood): “The Vermillion wastewater treatment plant also experienced significant damage, forcing the release of untreated water into the Vermillion River.” Source: NOAA Storm Events Database
• May 12, 2022, Lake (thunderstorm wind): “Several 500 lb. tanks from an agricultural supply story were blown across a four lane highway into the water treatment plant.” Source: NOAA Storm Events Database

Checked September 2026.