{"schema_version":"1.2","pwsid":"WI2300145","system_name":"KNOLLS WATER COOPERATIVE","city":"POWERS LAKE","state":"WI","population_served":400,"source_type":"GW","summary":"KNOLLS WATER COOPERATIVE serves approximately 400 people in POWERS LAKE, Wisconsin. Based on contaminant analyses from DNR, EPA ECHO, 2 contaminants have been measured above federal EPA standards (MCL) and 4 exceed health-based guidelines. The most significant finding is PFOA (Perfluorooctanoic Acid) at 6.9 ng/L, which is 1.7x 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":"2026-07-15"},"contaminants_tested":55,"contaminants_detected":17,"exceedances":2,"guideline_exceedances":4,"contaminants":[{"name":"Chlorine (free)","code":"0700","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.01,"unit":"mg/L","sample_date":"2026-07-15","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 (total residual)","code":"0700_TOTAL","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.02,"unit":"mg/L","sample_date":"2026-07-15","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":"Chloramines","code":"0600","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.03,"unit":"mg/L","sample_date":"2026-07-15","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":5.66,"unit":"mg/L","sample_date":"2026-06-24","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":"PFHpA (Perfluoroheptanoic Acid)","code":"PFHPA","cas_number":null,"group":"pfas","section":"other_detected","measured_value":3,"unit":"ng/L","sample_date":"2026-04-09","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":0.86,"unit":"ug/L","sample_date":"2022-09-22","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":6.94,"unit":"ug/L","sample_date":"2025-08-08","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":"Uranium","code":"4006","cas_number":"7440-61-1","group":"radionuclides","section":"guideline_exceedance","measured_value":0.56,"unit":"ug/L","sample_date":"2021-05-20","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":"Gross Alpha Radiation (excluding Radon and Uranium)","code":"4000_EXCL","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":0.8267,"unit":"pCi/L","sample_date":"2021-05-20","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":"Combined Radium (226+228)","code":"4010","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":1.68,"unit":"pCi/L","sample_date":"2021-05-20","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":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.00245,"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":190,"unit":"ug/L","sample_date":"2024-07-22","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":"PFHxS (Perfluorohexane Sulfonate)","code":"PFHXS","cas_number":"355-46-4","group":"pfas","section":"pfas","measured_value":4.5,"unit":"ng/L","sample_date":"2026-04-09","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.01,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.01,"status":"below_limits","detection_limit":null},{"name":"PFOS (Perfluorooctane Sulfonate)","code":"PFOS","cas_number":"1763-23-1","group":"pfas","section":"legal_violation","measured_value":5.9,"unit":"ng/L","sample_date":"2026-04-09","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.004,"status":"exceeds_legal_limit","detection_limit":null},{"name":"PFOA (Perfluorooctanoic Acid)","code":"PFOA","cas_number":"335-67-1","group":"pfas","section":"legal_violation","measured_value":6.9,"unit":"ng/L","sample_date":"2026-04-09","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.004,"status":"exceeds_legal_limit","detection_limit":null},{"name":"PFHxA (Perfluorohexanoic Acid)","code":"PFHXA","cas_number":"307-24-4","group":"pfas","section":"pfas","measured_value":9.9,"unit":"ng/L","sample_date":"2026-04-09","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"PFBS (Perfluorobutane Sulfonate)","code":"PFBS","cas_number":"375-73-5","group":"pfas","section":"pfas","measured_value":13,"unit":"ng/L","sample_date":"2026-04-09","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null}],"sources":[{"name":"DNR","url":"https://apps.dnr.wi.gov/dwsportalpub"},{"name":"EPA ECHO","url":"https://echo.epa.gov/"}],"pfas_combined_display":{"value":12.8,"unit":"ng/L","sample_date":"2026-04-09","note":"Legacy 2016 EPA Health Advisory combined PFOA+PFOS metric. Not a current MCL."},"well_counts":{"active":2,"retired":0,"facilities_synced_at":"2026-09-05T13:11:48.807Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":{"value":0.4565,"compounds_used":["PFHXS","PFBS"],"is_partial":true,"threshold":1,"components":[{"code":"PFHXS","value_ng_l":4.5,"hbwc_ng_l":10,"ratio":0.45},{"code":"PFBS","value_ng_l":13,"hbwc_ng_l":2000,"ratio":0.0065}]},"tthm_lraa":[],"haa5_lraa":[]}