Tapcensus

Gillette, City of

Community water system in Gillette, Campbell County, Wyoming, serving 32,222 people from ground water. 1 rule violated in the past three years. Owned by local government. System ID WY5600019.

People served 32,222 ground water
Rules violated, past 3 years 1 one rule can carry several violations
Unresolved 0 rules still in violation, EPA data updated Oct 7, 2026
Quarters with violations 1 of the last 12 quarters

Quarterly compliance history

–Q4
2023
VQ1
2024
–Q2
2024
–Q3
2024
–Q4
2024
–Q1
2025
–Q2
2025
–Q3
2025
–Q4
2025
–Q1
2026
–Q2
2026
–Q3
2026
UQ4
2026
–No violation identified VViolation identified SSerious violator (EPA enforcement priority) UUndetermined Oldest quarter on the left. Quarters 1 to 12 are the twelve most recently completed quarters at EPA's last data refresh; the 13th is the current quarter up to that date, which EPA reports as undetermined.

Rules violated in the past three years

Oct to Dec 2023 to Oct to Dec 2026

Chlorine (MRDL)

This entry tracks violations of the Maximum Residual Disinfectant Level (MRDL) for chlorine — meaning too much disinfectant residual in the distribution…
EPA rule code 0999 · Treatment Technique

What it means: This entry tracks violations of the Maximum Residual Disinfectant Level (MRDL) for chlorine — meaning too much disinfectant residual in the distribution system, not too little. Chlorine is added to water to kill pathogens, but excess residual can react with organic matter to form disinfection byproducts.

Health effects: Acute high-dose exposure to chlorinated water can cause eye and nose irritation, stomach discomfort, and nausea. Chronic exposure above the MRDL is primarily a concern because elevated chlorine accelerates formation of trihalomethanes and haloacetic acids, which are associated with increased cancer risk over time.

Limit: MRDL: 4.0 mg/L as an annual average

About this rule
About this data

EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several in the same period. Unresolved means still in violation at EPA's latest data refresh. Measured contaminant levels are not part of this record; each system publishes them in its annual Consumer Confidence Report.

Service area from EPA's Public Water System Service Area Boundaries dataset: Federal agency. The system's location is the centre of the service area EPA publishes for the system.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Wyoming records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.