{"schema_version":"1.2","pwsid":"IL1615387","system_name":"ROCK ISLAND ARSENAL, US ARMY","city":"ROCK ISLAND","state":"IL","population_served":7800,"source_type":"SW","summary":"ROCK ISLAND ARSENAL, US ARMY serves approximately 7,800 people in ROCK ISLAND, Illinois. Based on contaminant analyses from DNR, 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 PFOA (Perfluorooctanoic Acid) at 0.0046 ug/L, which is 1.2x the EPA legal limit. Data is drawn from source-level compliance monitoring and covers 2017 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2017-12-31","end":"2026-12-31"},"contaminants_tested":37,"contaminants_detected":9,"exceedances":1,"guideline_exceedances":1,"contaminants":[{"name":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":39.17,"unit":"ug/L","sample_date":"2026-08-10","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":21.98,"unit":"ug/L","sample_date":"2026-08-10","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":"Nitrate (as N)","code":"NITRATE","cas_number":"14797-55-8","group":"inorganics","section":"other_detected","measured_value":2.32,"unit":"mg/L","sample_date":"2026-04-13","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":"Barium","code":"BARIUM","cas_number":"7440-39-3","group":"inorganics","section":"other_detected","measured_value":0.0132,"unit":"mg/L","sample_date":"2026-02-09","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":"Toc","code":"TOC","cas_number":null,"group":"other","section":"other_detected","measured_value":6.7,"unit":"mg/L","sample_date":"2026-09-07","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":"other_detected","measured_value":0,"unit":"mg/L","sample_date":"2026-12-31","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":"Copper (90th Percentile)","code":"COPPER","cas_number":"7440-50-8","group":"lead_copper","section":"other_detected","measured_value":41.7,"unit":"ug/L","sample_date":"2026-07-20","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},{"name":"PFOA (Perfluorooctanoic Acid)","code":"PFOA","cas_number":"335-67-1","group":"pfas","section":"legal_violation","measured_value":0.0046,"unit":"ug/L","sample_date":"2023-11-07","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},{"name":"PFBA (Perfluorobutanoic Acid)","code":"PFBA","cas_number":null,"group":"pfas","section":"pfas","measured_value":0.015,"unit":"ug/L","sample_date":"2023-11-07","source":"EPA UCMR5","source_scope":"federal_program","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":0.005}],"sources":[{"name":"DNR","url":"https://apps.dnr.wi.gov/dwsportalpub"},{"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":0,"retired":2,"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 S2HH2","value":21.98,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q2","2026Q3"],"sample_count":4,"mcl":80,"exceeds_mcl":false},{"monitoring_point":"Well S2HT1","value":21.98,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q2","2026Q3"],"sample_count":4,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"Well S2HH2","value":39.17,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q2","2026Q3"],"sample_count":4,"mcl":60,"exceeds_mcl":false},{"monitoring_point":"Well S2HT1","value":37.25,"unit":"ug/L","quarters_used":["2025Q4","2026Q1","2026Q2","2026Q3"],"sample_count":4,"mcl":60,"exceeds_mcl":false}]}