{"schema_version":"1.2","pwsid":"IL1130750","system_name":"LE ROY","city":"LEROY","state":"IL","population_served":3498,"source_type":"GW","summary":"LE ROY serves approximately 3,498 people in LEROY, Illinois. Based on contaminant analyses from DNR, WQP, EPA ECHO, EPA UCMR5, the most recent monitoring readings are within federal EPA standards (MCL), but this system has active MCL violations on record for 1 contaminant. 3 contaminants exceed health-based guidelines. The most significant finding is Lead (90th Percentile) at 0.013 mg/L, which is 65x the health guideline. Data is drawn from source-level compliance monitoring and covers 1996 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"1996-06-03","end":"2026-10-06"},"contaminants_tested":39,"contaminants_detected":9,"exceedances":0,"guideline_exceedances":3,"contaminants":[{"name":"Total Trihalomethanes (TTHMs)","code":"2950","cas_number":null,"group":"dbps","section":"other_detected","measured_value":32.73,"unit":"ug/L","sample_date":"2026-10-06","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":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":33.32,"unit":"ug/L","sample_date":"2026-10-06","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":"Nitrate (as N)","code":"NITRATE","cas_number":"14797-55-8","group":"inorganics","section":"other_detected","measured_value":0.73,"unit":"mg/L","sample_date":"2026-08-12","source":"DNR","source_scope":"source_monitoring","health_guideline_value":10,"health_guideline_source":"EPA MCLG","epa_mcl_value":10,"status":"below_limits","detection_limit":null},{"name":"Arsenic","code":"ARSENIC","cas_number":"7440-38-2","group":"inorganics","section":"guideline_exceedance","measured_value":0.0038,"unit":"mg/L","sample_date":"2026-07-29","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.000004,"health_guideline_source":"OEHHA PHG","epa_mcl_value":0.01,"status":"exceeds_guideline","detection_limit":null},{"name":"Barium","code":"BARIUM","cas_number":"7440-39-3","group":"inorganics","section":"other_detected","measured_value":0.027,"unit":"mg/L","sample_date":"2026-07-29","source":"DNR","source_scope":"source_monitoring","health_guideline_value":1,"health_guideline_source":"OEHHA PHG 2003 (hypertension endpoint)","epa_mcl_value":2,"status":"below_limits","detection_limit":null},{"name":"Fluoride (natural)","code":"FLUORIDE","cas_number":"16984-48-8","group":"inorganics","section":"other_detected","measured_value":0.302,"unit":"mg/L","sample_date":"2026-07-29","source":"DNR","source_scope":"source_monitoring","health_guideline_value":4,"health_guideline_source":"EPA MCLG","epa_mcl_value":4,"status":"below_limits","detection_limit":null},{"name":"Chromium (total)","code":"CHROMIUM","cas_number":"7440-47-3","group":"inorganics","section":"other_detected","measured_value":0.08,"unit":"ug/L","sample_date":"2011-06-16","source":"WQP","source_scope":"regional_groundwater","health_guideline_value":0.1,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.1,"status":"below_limits","detection_limit":null},{"name":"Orthophosphate","code":"ORTHOPHOSPHATE","cas_number":null,"group":"other","section":"other_detected","measured_value":920,"unit":"ug/L","sample_date":"2026-09-22","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.013,"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":"CU90","cas_number":"7440-50-8","group":"lead_copper","section":"guideline_exceedance","measured_value":2.7,"unit":"mg/L","sample_date":"2023-06-30","source":"EPA ECHO","source_scope":"federal_program","health_guideline_value":0.3,"health_guideline_source":"OEHHA PHG","epa_mcl_value":null,"status":"exceeds_guideline","detection_limit":null}],"sources":[{"name":"DNR","url":"https://apps.dnr.wi.gov/dwsportalpub"},{"name":"WQP","url":"https://www.waterqualitydata.us/"},{"name":"EPA ECHO","url":"https://echo.epa.gov/"},{"name":"EPA UCMR5","url":"https://www.epa.gov/dwucmr/fifth-unregulated-contaminant-monitoring-rule"}],"pfas_combined_display":null,"well_counts":{"active":3,"retired":3,"facilities_synced_at":"2026-11-02T01:09:07.370Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[{"monitoring_point":"Well S2HT1","value":32.73,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q3","2026Q4"],"sample_count":4,"mcl":80,"exceeds_mcl":false},{"monitoring_point":"Well S2HH1","value":13.34,"unit":"ug/L","quarters_used":["2026Q1","2026Q2","2026Q3","2026Q4"],"sample_count":4,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"Well S2HT1","value":33.32,"unit":"ug/L","quarters_used":["2026Q1","2026Q2","2026Q3","2026Q4"],"sample_count":4,"mcl":60,"exceeds_mcl":false},{"monitoring_point":"Well S2HH1","value":8.85,"unit":"ug/L","quarters_used":["2026Q1","2026Q2","2026Q3","2026Q4"],"sample_count":4,"mcl":60,"exceeds_mcl":false}]}