{"schema_version":"1.2","pwsid":"WI1570100","system_name":"PRAIRIE DU SAC WATERWORKS","city":"PRAIRIE DU SAC","state":"WI","population_served":4006,"source_type":"GW","summary":"PRAIRIE DU SAC WATERWORKS serves approximately 4,006 people in PRAIRIE DU SAC, Wisconsin. Based on contaminant analyses from DNR, WQP, EPA ECHO, EPA UCMR5, the most recent monitoring readings are within federal EPA standards (MCL), but this system has active MCL violations on record for 1 contaminant. 2 contaminants exceed health-based guidelines. The most significant finding is Uranium at 4.6 ug/L, which is 9.2x 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":"2013-08-21","end":"2026-09-16"},"contaminants_tested":164,"contaminants_detected":15,"exceedances":0,"guideline_exceedances":2,"contaminants":[{"name":"Chlorine (free)","code":"0700","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.22,"unit":"mg/L","sample_date":"2026-09-16","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":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":0.21,"unit":"ug/L","sample_date":"2025-07-14","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":1.38,"unit":"ug/L","sample_date":"2025-07-14","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":"Fluoride (natural)","code":"FLUORIDE","cas_number":"16984-48-8","group":"inorganics","section":"other_detected","measured_value":0.0761,"unit":"mg/L","sample_date":"2026-09-01","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":"Nitrate (as N)","code":"NITRATE","cas_number":"14797-55-8","group":"inorganics","section":"other_detected","measured_value":0.078,"unit":"mg/L","sample_date":"2024-06-26","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":"Selenium","code":"1045","cas_number":null,"group":"inorganics","section":"other_detected","measured_value":0.0015,"unit":"mg/L","sample_date":"2023-04-10","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.05,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.05,"status":"below_limits","detection_limit":null},{"name":"Chromium (total)","code":"CHROMIUM","cas_number":"7440-47-3","group":"inorganics","section":"other_detected","measured_value":190,"unit":"ug/L","sample_date":"2022-05-24","source":"WQP","source_scope":"regional_groundwater","health_guideline_value":0.1,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.1,"status":"exceeds_legal_limit","detection_limit":null},{"name":"Nickel","code":"1036","cas_number":null,"group":"inorganics","section":"other_detected","measured_value":0.0036,"unit":"mg/L","sample_date":"2024-06-26","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.012,"health_guideline_source":"OEHHA PHG","epa_mcl_value":null,"status":"below_limits","detection_limit":null},{"name":"Arsenic","code":"ARSENIC","cas_number":"7440-38-2","group":"inorganics","section":"other_detected","measured_value":7.71,"unit":"ug/L","sample_date":"2022-06-01","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":0.0257,"unit":"mg/L","sample_date":"2026-04-13","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":"guideline_exceedance","measured_value":4.6,"unit":"ug/L","sample_date":"2026-04-13","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.0005,"health_guideline_source":"OEHHA PHG","epa_mcl_value":0.03,"status":"exceeds_guideline","detection_limit":null},{"name":"Combined Radium (226+228)","code":"4010","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":4.07,"unit":"pCi/L","sample_date":"2026-04-13","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":5,"status":"approaching","detection_limit":null},{"name":"Gross Beta","code":"4002","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":6.03,"unit":"pCi/L","sample_date":"2026-04-13","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":50,"status":"below_limits","detection_limit":null},{"name":"Gross Alpha Radiation (excluding Radon and Uranium)","code":"4000_EXCL","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":8.02,"unit":"pCi/L","sample_date":"2026-04-13","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":15,"status":"below_limits","detection_limit":null},{"name":"Radon","code":"RADON","cas_number":"10043-92-2","group":"radionuclide","section":"other_detected","measured_value":178,"unit":"pCi/L","sample_date":"2024-06-26","source":"DNR","source_scope":"source_monitoring","health_guideline_value":300,"health_guideline_source":"EPA proposed MCL (1999, never finalized)","epa_mcl_value":null,"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":0.0014,"unit":"mg/L","sample_date":"2023-09-30","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":180,"unit":"ug/L","sample_date":"2026-07-14","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}],"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":2,"facilities_synced_at":"2026-10-12T00:17:03.546Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[{"monitoring_point":"system_wide","value":1.38,"unit":"ug/L","quarters_used":["2023Q3","2024Q3","2025Q3","2026Q3"],"sample_count":4,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"system_wide","value":0.21,"unit":"ug/L","quarters_used":["2022Q3","2024Q3","2025Q3","2026Q3"],"sample_count":4,"mcl":60,"exceeds_mcl":false}]}