Dorchester
Community water system in Dorchester, Macoupin County, Illinois, serving 540 people from surface water purchased. 2 rules violated in the past three years. Owned by local government.
Quarterly compliance history
2023
2023
2024
2024
2024
2024
2025
2025
2025
2025
2026
2026
2026
Rules violated in the past three years
Jul to Sep 2023 to Jul to Sep 2026
Long Term 2 Enhanced Surface Water Treatment Rule
Treatment Technique Violation
Health-based
1 violation, Jan 2026 to Mar 2026
Long Term 2 Enhanced Surface Water Treatment Rule
Treatment Technique Violation Health-based1 violation, Jan 2026 to Mar 2026
Treatment Technique Violation, health-based: 1 violation, Jan 2026 to Mar 2026. The system did not carry out a required treatment process or corrective action.
What the rule requires: The LT2 ESWTR (2006) required all surface water and GWUDI systems to monitor source water for Cryptosporidium, then apply additional treatment based on measured concentrations. Higher-bin systems (more oocysts detected) must install advanced treatment — UV disinfection, ozone, or membrane filtration — beyond the original SWTR requirements.
Health effects: Cryptosporidium is a chlorine-resistant protozoan parasite that causes cryptosporidiosis — severe watery diarrhea, cramping, nausea, and fever. In immunocompromised individuals (HIV/AIDS, transplant recipients), it can be life-threatening and prolonged. Infants and the elderly are also at elevated risk. LT2 violations indicate failure to complete monitoring or apply the required additional treatment tier. Limit: Treatment technique — additional Cryptosporidium treatment based on bin classification
About this rule
Stage 2 Disinfectants and Disinfection Byproducts Rule
Monitoring and Reporting
2 violations, Apr 2025 to Oct 2025 · 2 contaminants
Stage 2 Disinfectants and Disinfection Byproducts Rule
Monitoring and Reporting2 violations, Apr 2025 to Oct 2025 · 2 contaminants
Monitoring and Reporting: 2 violations, Apr 2025 to Oct 2025. The system did not complete required monitoring, or did not report the results on time. This does not show that a contaminant was found.
Contaminants on the record: Total Haloacetic Acids (HAA5), TTHM (Total Trihalomethanes).
Lead and copper at the tap
The 90th percentile of the tap samples the system collected in its latest monitoring period, against EPA's action level. Levels vary between homes.
Action level 0.015 mg/L · Jan to Dec 2025
About this data
Rules violated and the list above come from EPA's SDWIS violation records, one row per violation and contaminant, grouped by the rule each row belongs to. A violation counts when its non-compliance period ended on or after Jul 1, 2023, the start of the thirteen quarters ECHO's three-year figures cover, or is still open; it is unresolved when it was still open at EPA's data refresh on Oct 7, 2026. EPA's rule code 500, "Not Regulated", is left out, as in ECHO's counts. Each rule's violation count is EPA's, and one rule can carry several: a missed monitoring round for a group of contaminants is one violation per contaminant and period. Category names are EPA's violation categories.
ECHO's own summary count of rules violated agrees with this grouping for 98.8% of active systems nationally, and its count of rules being violated for 98.7%; where they differ, the figures here follow the rows listed.
A measured value shown with a rule is the sample result EPA recorded with that violation (SDWIS viol_measure), against the limit EPA recorded on the same row (state_mcl), both in EPA's unit as written; violations without a recorded value, such as missed monitoring, show none. Other measured contaminant levels are not part of this record; each system publishes them in its annual Consumer Confidence Report.
Lead and copper are the newest 90th-percentile results in EPA's SDWA data download (LCR_SAMPLES, codes PB90 and CU90): for each monitoring period a system reports the 90th-percentile value of its tap samples, which EPA compares with its action level of 0.015 mg/L for lead and 1.3 mg/L for copper (40 CFR 141.80). A result is not a measurement of any one tap.
Service area from EPA's Public Water System Service Area Boundaries dataset: Decision Tree method, 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 Illinois 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.