{"schema_version":"1.2","pwsid":"IL1630350","system_name":"DUPO","city":"DUPO","state":"IL","population_served":4684,"source_type":"GW","summary":"DUPO serves approximately 4,684 people in DUPO, Illinois. Based on contaminant analyses from EPA ECHO, EPA UCMR5, 1 contaminant has been measured above federal EPA standards (MCL) and 1 exceeds health-based guidelines. The most significant finding is PFOS (Perfluorooctane Sulfonate) at 0.0045 ug/L, which is 1.1x the EPA legal limit. Data is drawn from source-level compliance monitoring and covers 2017 through 2025. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2017-12-31","end":"2025-11-03"},"contaminants_tested":31,"contaminants_detected":5,"exceedances":1,"guideline_exceedances":1,"contaminants":[{"name":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"other_detected","measured_value":0,"unit":"mg/L","sample_date":"2023-12-31","source":"EPA ECHO","source_scope":"federal_program","health_guideline_value":0.0002,"health_guideline_source":"OEHHA PHG","epa_mcl_value":null,"status":"below_limits","detection_limit":null},{"name":"PFBS (Perfluorobutane Sulfonate)","code":"PFBS","cas_number":"375-73-5","group":"pfas","section":"pfas","measured_value":0.0037,"unit":"ug/L","sample_date":"2025-11-03","source":"EPA UCMR5","source_scope":"federal_program","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":0.003},{"name":"PFHxS (Perfluorohexane Sulfonate)","code":"PFHXS","cas_number":"355-46-4","group":"pfas","section":"pfas","measured_value":0.0031,"unit":"ug/L","sample_date":"2025-05-06","source":"EPA UCMR5","source_scope":"federal_program","health_guideline_value":0.01,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.01,"status":"below_limits","detection_limit":0.003},{"name":"Lithium","code":"lithium","cas_number":null,"group":"other","section":"pfas","measured_value":23,"unit":"ug/L","sample_date":"2025-11-03","source":"EPA UCMR5","source_scope":"federal_program","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":9},{"name":"PFOS (Perfluorooctane Sulfonate)","code":"PFOS","cas_number":"1763-23-1","group":"pfas","section":"legal_violation","measured_value":0.0045,"unit":"ug/L","sample_date":"2025-11-03","source":"EPA UCMR5","source_scope":"federal_program","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.004,"status":"exceeds_legal_limit","detection_limit":0.004}],"sources":[{"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":2,"retired":0,"facilities_synced_at":"2026-09-06T14:49:36.593Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":{"value":0.3119,"compounds_used":["PFHXS","PFBS"],"is_partial":true,"threshold":1,"components":[{"code":"PFHXS","value_ng_l":3.1,"hbwc_ng_l":10,"ratio":0.31},{"code":"PFBS","value_ng_l":3.7,"hbwc_ng_l":2000,"ratio":0.0019}]},"tthm_lraa":[],"haa5_lraa":[]}