{"schema_version":"1.2","pwsid":"IL0374850","system_name":"SANDWICH","city":"SANDWICH","state":"IL","population_served":7156,"source_type":"GW","summary":"SANDWICH serves approximately 7,156 people in SANDWICH, Illinois. Based on contaminant analyses from DNR, WQP, EPA ECHO, EPA UCMR5, 1 contaminant has been measured above federal EPA standards (MCL) and 2 exceed health-based guidelines. The most significant finding is Combined Radium (226+228) at 9.26 pCi/L, which is 1.9x the EPA legal limit. 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":"1996-08-06","end":"2026-09-15"},"contaminants_tested":37,"contaminants_detected":7,"exceedances":1,"guideline_exceedances":2,"contaminants":[{"name":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":4,"unit":"ug/L","sample_date":"2026-08-20","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":14.04,"unit":"ug/L","sample_date":"2026-08-20","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":"cis-1,2-Dichloroethylene","code":"2943","cas_number":"156-59-2","group":"vocs","section":"other_detected","measured_value":1.3,"unit":"ug/L","sample_date":"2026-04-23","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.07,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.07,"status":"below_limits","detection_limit":null},{"name":"Combined Radium (226+228)","code":"4010","cas_number":null,"group":"radionuclides","section":"legal_violation","measured_value":9.26,"unit":"pCi/L","sample_date":"2025-11-13","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":5,"status":"exceeds_legal_limit","detection_limit":null},{"name":"Gross Alpha","code":"4000","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":10.1,"unit":"pCi/L","sample_date":"2025-11-13","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":15,"status":"below_limits","detection_limit":null},{"name":"Fluoride (natural)","code":"FLUORIDE","cas_number":"16984-48-8","group":"inorganics","section":"other_detected","measured_value":0.33,"unit":"mg/L","sample_date":"2017-05-30","source":"WQP","source_scope":"regional_groundwater","health_guideline_value":4,"health_guideline_source":"EPA MCLG","epa_mcl_value":4,"status":"below_limits","detection_limit":null},{"name":"Arsenic","code":"ARSENIC","cas_number":"7440-38-2","group":"inorganics","section":"other_detected","measured_value":4.5,"unit":"ug/L","sample_date":"2017-05-30","source":"WQP","source_scope":"regional_groundwater","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":0.282,"unit":"mg/L","sample_date":"2017-05-30","source":"WQP","source_scope":"regional_groundwater","health_guideline_value":1,"health_guideline_source":"OEHHA PHG 2003 (hypertension endpoint)","epa_mcl_value":2,"status":"below_limits","detection_limit":null},{"name":"Nitrate (as N)","code":"NITRATE","cas_number":"14797-55-8","group":"inorganics","section":"other_detected","measured_value":0.42,"unit":"mg/L","sample_date":"2014-09-09","source":"WQP","source_scope":"regional_groundwater","health_guideline_value":10,"health_guideline_source":"EPA MCLG","epa_mcl_value":10,"status":"below_limits","detection_limit":null},{"name":"Chromium (total)","code":"CHROMIUM","cas_number":"7440-47-3","group":"inorganics","section":"other_detected","measured_value":0.5,"unit":"ug/L","sample_date":"2012-08-08","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":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.002,"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":250,"unit":"ug/L","sample_date":"2026-09-15","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.3,"health_guideline_source":"OEHHA PHG","epa_mcl_value":null,"status":"approaching","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":0,"facilities_synced_at":"2026-11-02T01:09:07.370Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[],"haa5_lraa":[]}