{"schema_version":"1.2","pwsid":"WI6090458","system_name":"CORNELL WATERWORKS","city":"CORNELL","state":"WI","population_served":1390,"source_type":"GW","summary":"CORNELL WATERWORKS serves approximately 1,390 people in CORNELL, Wisconsin. Based on contaminant analyses from DNR, WQP, EPA ECHO, 0 contaminants have been measured above federal EPA standards (MCL) and 1 exceeds health-based guidelines. The most significant finding is Lead (90th Percentile) at 0.0023 mg/L, which is 11.5x the health guideline. Data is drawn from source-level compliance monitoring and covers 2013 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2013-08-28","end":"2026-03-17"},"contaminants_tested":16,"contaminants_detected":15,"exceedances":0,"guideline_exceedances":1,"contaminants":[{"name":"Chlorine (free)","code":"0700","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.48,"unit":"mg/L","sample_date":"2026-03-17","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":"Fluoride (natural)","code":"FLUORIDE","cas_number":"16984-48-8","group":"inorganics","section":"other_detected","measured_value":0.71,"unit":"mg/L","sample_date":"2026-03-03","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":"Barium","code":"BARIUM","cas_number":"7440-39-3","group":"inorganics","section":"other_detected","measured_value":0.02,"unit":"mg/L","sample_date":"2026-02-24","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":"Uranium","code":"4006","cas_number":"7440-61-1","group":"radionuclides","section":"other_detected","measured_value":0.061,"unit":"ug/L","sample_date":"2026-02-24","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.0005,"health_guideline_source":"OEHHA PHG","epa_mcl_value":0.03,"status":"below_limits","detection_limit":null},{"name":"Nitrate (as N)","code":"NITRATE","cas_number":"14797-55-8","group":"inorganics","section":"other_detected","measured_value":0.33,"unit":"mg/L","sample_date":"2026-02-24","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":"Combined Radium (226+228)","code":"4010","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":0.3596,"unit":"pCi/L","sample_date":"2026-02-24","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":5,"status":"below_limits","detection_limit":null},{"name":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":10.5,"unit":"ug/L","sample_date":"2026-02-17","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":46.2,"unit":"ug/L","sample_date":"2026-02-17","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":"1,2,4-Trimethylbenzene","code":"1_2_4_TRIMETHYLBENZENE","cas_number":null,"group":"vocs","section":"other_detected","measured_value":0.28,"unit":"ug/L","sample_date":"2025-02-21","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"Toluene","code":"2964","cas_number":null,"group":"other","section":"other_detected","measured_value":0.51,"unit":"ug/L","sample_date":"2025-02-21","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"Total Xylenes","code":"2969","cas_number":"1330-20-7","group":"organic","section":"other_detected","measured_value":0.77,"unit":"ug/L","sample_date":"2025-02-21","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.5,"health_guideline_source":"WHO Guideline","epa_mcl_value":10,"status":"below_limits","detection_limit":null},{"name":"Ethylbenzene","code":"2966","cas_number":null,"group":"other","section":"other_detected","measured_value":3.5,"unit":"ug/L","sample_date":"2022-08-16","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"Arsenic","code":"ARSENIC","cas_number":"7440-38-2","group":"inorganics","section":"other_detected","measured_value":0.08,"unit":"ug/L","sample_date":"2013-08-28","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":"Chromium (total)","code":"CHROMIUM","cas_number":"7440-47-3","group":"inorganics","section":"other_detected","measured_value":0.31,"unit":"ug/L","sample_date":"2013-08-28","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":0.0023,"unit":"mg/L","sample_date":"2024-09-30","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":230,"unit":"ug/L","sample_date":"2024-08-07","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":"PFOS (Perfluorooctane Sulfonate)","code":"PFOS","cas_number":"1763-23-1","group":"pfas","section":"pfas","measured_value":0.36,"unit":"ng/L","sample_date":"2023-05-16","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.004,"status":"below_limits","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/"}],"pfas_combined_display":{"value":0.36,"unit":"ng/L","sample_date":"2023-05-16","note":"Legacy 2016 EPA Health Advisory combined PFOA+PFOS metric. Not a current MCL."},"well_counts":{"active":2,"retired":1,"facilities_synced_at":"2026-04-11T13:48:07.246Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[{"monitoring_point":"system_wide","value":46.2,"unit":"ug/L","quarters_used":["2025Q2","2025Q3","2025Q4","2026Q1"],"sample_count":8,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"system_wide","value":10.5,"unit":"ug/L","quarters_used":["2025Q2","2025Q3","2025Q4","2026Q1"],"sample_count":8,"mcl":60,"exceeds_mcl":false}]}