{"schema_version":"1.2","pwsid":"IL1570150","system_name":"COULTERVILLE","city":"COULTERVILLE","state":"IL","population_served":1052,"source_type":"SW","summary":"COULTERVILLE serves approximately 1,052 people in COULTERVILLE, Illinois. Based on contaminant analyses from DNR, EPA ECHO, 0 contaminants have been measured above federal EPA standards (MCL) and 1 exceeds health-based guidelines. The most significant finding is Lead (90th Percentile) at 0.0016 mg/L, which is 8x the health guideline. Data is drawn from source-level compliance monitoring and covers 2016 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2016-12-31","end":"2026-08-04"},"contaminants_tested":4,"contaminants_detected":4,"exceedances":0,"guideline_exceedances":1,"contaminants":[{"name":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":24.37,"unit":"ug/L","sample_date":"2026-08-04","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.0001,"health_guideline_source":"EWG Health Guideline","epa_mcl_value":0.06,"status":"below_limits","detection_limit":null},{"name":"Total Trihalomethanes (TTHMs)","code":"2950","cas_number":null,"group":"dbps","section":"other_detected","measured_value":30.13,"unit":"ug/L","sample_date":"2026-08-04","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.00015,"health_guideline_source":"EWG Health Guideline","epa_mcl_value":0.08,"status":"below_limits","detection_limit":null},{"name":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.0016,"unit":"mg/L","sample_date":"2026-06-30","source":"EPA ECHO","source_scope":"federal_program","health_guideline_value":0.0002,"health_guideline_source":"OEHHA PHG","epa_mcl_value":null,"status":"exceeds_guideline","detection_limit":null},{"name":"Copper (90th Percentile)","code":"COPPER","cas_number":"7440-50-8","group":"lead_copper","section":"other_detected","measured_value":10,"unit":"ug/L","sample_date":"2026-05-11","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.3,"health_guideline_source":"OEHHA PHG","epa_mcl_value":null,"status":"below_limits","detection_limit":null}],"sources":[{"name":"DNR","url":"https://apps.dnr.wi.gov/dwsportalpub"},{"name":"EPA ECHO","url":"https://echo.epa.gov/"}],"pfas_combined_display":null,"well_counts":{"active":0,"retired":0,"facilities_synced_at":"2026-10-26T01:13:06.376Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[{"monitoring_point":"Well S2HT1","value":30.13,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q2","2026Q3"],"sample_count":4,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"Well S2HH1","value":24.37,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q2","2026Q3"],"sample_count":4,"mcl":60,"exceeds_mcl":false}]}