{"schema_version":"1.2","pwsid":"WI1140016","system_name":"HIDDEN MEADOWS","city":"WATERTOWN","state":"WI","population_served":166,"source_type":"GW","summary":"HIDDEN MEADOWS serves approximately 166 people in WATERTOWN, Wisconsin. Based on contaminant analyses from DNR, EPA ECHO, 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 5.05 pCi/L, which is 1x the EPA legal limit. Data is drawn from source-level compliance monitoring and covers 2018 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2018-09-30","end":"2026-09-09"},"contaminants_tested":118,"contaminants_detected":17,"exceedances":1,"guideline_exceedances":2,"contaminants":[{"name":"Chlorine (total residual)","code":"0700_TOTAL","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.06,"unit":"mg/L","sample_date":"2025-01-27","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":"Chlorine (free)","code":"0700","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.11,"unit":"mg/L","sample_date":"2026-03-12","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":"Uranium","code":"4006","cas_number":"7440-61-1","group":"radionuclides","section":"other_detected","measured_value":0.073,"unit":"ug/L","sample_date":"2026-07-22","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":"Combined Radium (226+228)","code":"4010","cas_number":null,"group":"radionuclides","section":"legal_violation","measured_value":5.05,"unit":"pCi/L","sample_date":"2026-07-22","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 Radiation (excluding Radon and Uranium)","code":"4000_EXCL","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":7.42,"unit":"pCi/L","sample_date":"2026-07-22","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":"Nitrate (as N)","code":"NITRATE","cas_number":"14797-55-8","group":"inorganics","section":"other_detected","measured_value":0.075,"unit":"mg/L","sample_date":"2024-06-13","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":"Total Trihalomethanes (TTHMs)","code":"2950","cas_number":null,"group":"dbps","section":"other_detected","measured_value":1.99,"unit":"ug/L","sample_date":"2025-09-09","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":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":2,"unit":"ug/L","sample_date":"2025-09-09","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":"Radon","code":"RADON","cas_number":"10043-92-2","group":"radionuclide","section":"other_detected","measured_value":234,"unit":"pCi/L","sample_date":"2025-09-09","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":"Arsenic","code":"ARSENIC","cas_number":"7440-38-2","group":"inorganics","section":"guideline_exceedance","measured_value":0.0014,"unit":"mg/L","sample_date":"2024-05-02","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.000004,"health_guideline_source":"OEHHA PHG","epa_mcl_value":0.01,"status":"exceeds_guideline","detection_limit":null},{"name":"Gross Beta","code":"4002","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":4.42,"unit":"pCi/L","sample_date":"2025-06-10","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":"Pentachlorophenol","code":"2041","cas_number":null,"group":"vocs","section":"other_detected","measured_value":0.021,"unit":"ug/L","sample_date":"2024-12-17","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.009,"health_guideline_source":"WHO Guideline","epa_mcl_value":0.001,"status":"below_limits","detection_limit":null},{"name":"Barium","code":"BARIUM","cas_number":"7440-39-3","group":"inorganics","section":"other_detected","measured_value":0.1075,"unit":"mg/L","sample_date":"2024-12-17","source":"DNR","source_scope":"source_monitoring","health_guideline_value":1,"health_guideline_source":"OEHHA PHG 2003 (hypertension 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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":6.2,"unit":"ug/L","sample_date":"2024-09-17","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":"EPA ECHO","url":"https://echo.epa.gov/"}],"pfas_combined_display":null,"well_counts":{"active":3,"retired":0,"facilities_synced_at":"2026-10-12T00:17:03.546Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[],"haa5_lraa":[]}