SD / Watertown
SD · Tap water records
Watertown tap water, in plain English
Here is what the EPA's own data shows about tap water in Watertown. According to EPA SDWIS data retrieved June 2026, Watertown is served by 2 active community water systems, together reported to serve about 27,510 people.
As of June 2026, EPA records show 16 violations across the community water system(s) serving Watertown, going back to the earliest EPA record. 4 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
What the EPA has on record, by system
Watertown Municipal Utilities
23,230 served · groundwater · PWSID SD4600356 - Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in July 2016. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
Sioux Rural Water System
4,280 served · groundwater · PWSID SD4600866 - Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in April 2020. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Gross Alpha, Excl. Radon and U: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2022. EPA records do not show all of these as returned to compliance.
- Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2022. EPA records do not show all of these as returned to compliance.
- Monitoring Combined Uranium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2022. EPA records do not show all of these as returned to compliance.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.