{"schema_version":"1.2","pwsid":"IL2010350","system_name":"ROCKTON","city":"ROCKTON","state":"IL","population_served":7685,"source_type":"GW","summary":"ROCKTON serves approximately 7,685 people in ROCKTON, Illinois. Based on contaminant analyses from EPA ECHO, EPA UCMR5, 1 contaminant has been measured above federal EPA standards (MCL) and 3 exceed health-based guidelines. The most significant finding is PFHxS (Perfluorohexane Sulfonate) at 0.012 ug/L, which is 1.2x the EPA legal limit. Data is drawn from source-level compliance monitoring and covers 2016 through 2025. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2016-12-31","end":"2025-12-31"},"contaminants_tested":32,"contaminants_detected":3,"exceedances":1,"guideline_exceedances":3,"contaminants":[{"name":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.0014,"unit":"mg/L","sample_date":"2025-12-31","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":1.7,"unit":"mg/L","sample_date":"2022-12-31","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},{"name":"PFHxS (Perfluorohexane Sulfonate)","code":"PFHXS","cas_number":"355-46-4","group":"pfas","section":"legal_violation","measured_value":0.012,"unit":"ug/L","sample_date":"2024-12-11","source":"EPA UCMR5","source_scope":"federal_program","health_guideline_value":0.01,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.01,"status":"exceeds_legal_limit","detection_limit":0.003}],"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":5,"retired":1,"facilities_synced_at":"2026-09-06T14:49:36.593Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":{"value":1.2,"compounds_used":["PFHXS"],"is_partial":true,"threshold":1,"components":[{"code":"PFHXS","value_ng_l":12,"hbwc_ng_l":10,"ratio":1.2}]},"tthm_lraa":[],"haa5_lraa":[]}