{"schema_version":"1.2","pwsid":"WI6100327","system_name":"GRANTON WATERWORKS","city":"GRANTON","state":"WI","population_served":349,"source_type":"GW","summary":"GRANTON WATERWORKS serves approximately 349 people in GRANTON, Wisconsin. Based on contaminant analyses from DNR, EPA ECHO, the most recent monitoring readings are within federal EPA standards (MCL), but this system has active MCL violations on record for 1 contaminant. 1 contaminant exceeds health-based guidelines. The most significant finding is Lead (90th Percentile) at 0.00225 mg/L, which is 11.2x the health guideline. Data is drawn from source-level compliance monitoring and covers 2016 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2016-09-30","end":"2026-09-21"},"contaminants_tested":86,"contaminants_detected":21,"exceedances":0,"guideline_exceedances":1,"contaminants":[{"name":"Chlorine (free)","code":"0700","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.51,"unit":"mg/L","sample_date":"2026-09-21","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":"Selenium","code":"1045","cas_number":null,"group":"inorganics","section":"other_detected","measured_value":0.0012,"unit":"mg/L","sample_date":"2026-08-18","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":"Alachlor","code":"2031","cas_number":null,"group":"vocs","section":"other_detected","measured_value":0.0092,"unit":"ug/L","sample_date":"2026-08-18","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.02,"health_guideline_source":"WHO Guideline","epa_mcl_value":0.002,"status":"below_limits","detection_limit":null},{"name":"Total Xylenes","code":"2969","cas_number":"1330-20-7","group":"organic","section":"other_detected","measured_value":0.29,"unit":"ug/L","sample_date":"2023-06-21","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":"Atrazine","code":"2050","cas_number":null,"group":"vocs","section":"other_detected","measured_value":0.01,"unit":"ug/L","sample_date":"2023-05-23","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.00015,"health_guideline_source":"OEHHA PHG 1999","epa_mcl_value":0.003,"status":"below_limits","detection_limit":null},{"name":"Nickel","code":"1036","cas_number":null,"group":"inorganics","section":"other_detected","measured_value":0.0022,"unit":"mg/L","sample_date":"2026-08-18","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":"Metolachlor","code":"2034","cas_number":null,"group":"vocs","section":"other_detected","measured_value":0.013,"unit":"ug/L","sample_date":"2026-08-18","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0.01,"health_guideline_source":"WHO Guideline","epa_mcl_value":null,"status":"below_limits","detection_limit":null},{"name":"Barium","code":"BARIUM","cas_number":"7440-39-3","group":"inorganics","section":"other_detected","measured_value":0.036,"unit":"mg/L","sample_date":"2026-08-18","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":"Fluoride (natural)","code":"FLUORIDE","cas_number":"16984-48-8","group":"inorganics","section":"other_detected","measured_value":0.17,"unit":"mg/L","sample_date":"2026-08-18","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":4,"unit":"mg/L","sample_date":"2026-08-18","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":"EDB (Ethylene Dibromide)","code":"2274","cas_number":null,"group":"other","section":"other_detected","measured_value":0.03,"unit":"ug/L","sample_date":"2025-04-01","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"PFHpA (Perfluoroheptanoic Acid)","code":"PFHPA","cas_number":null,"group":"pfas","section":"other_detected","measured_value":4.5,"unit":"ng/L","sample_date":"2026-08-10","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":5.25,"unit":"ug/L","sample_date":"2026-08-10","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":33.41,"unit":"ug/L","sample_date":"2026-08-10","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":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.00225,"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":58,"unit":"ug/L","sample_date":"2026-08-07","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":"PFHxS (Perfluorohexane Sulfonate)","code":"PFHXS","cas_number":"355-46-4","group":"pfas","section":"pfas","measured_value":0.46,"unit":"ng/L","sample_date":"2023-05-23","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":"PFBS (Perfluorobutane Sulfonate)","code":"PFBS","cas_number":"375-73-5","group":"pfas","section":"pfas","measured_value":0.99,"unit":"ng/L","sample_date":"2026-08-10","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"PFOS (Perfluorooctane Sulfonate)","code":"PFOS","cas_number":"1763-23-1","group":"pfas","section":"pfas","measured_value":1.4,"unit":"ng/L","sample_date":"2026-08-10","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},{"name":"PFOA (Perfluorooctanoic Acid)","code":"PFOA","cas_number":"335-67-1","group":"pfas","section":"pfas","measured_value":3.4,"unit":"ng/L","sample_date":"2026-08-10","source":"DNR","source_scope":"source_monitoring","health_guideline_value":0,"health_guideline_source":"EPA MCLG","epa_mcl_value":0.004,"status":"approaching","detection_limit":null},{"name":"PFHxA (Perfluorohexanoic Acid)","code":"PFHXA","cas_number":"307-24-4","group":"pfas","section":"pfas","measured_value":8,"unit":"ng/L","sample_date":"2026-08-10","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":4.8,"unit":"ng/L","sample_date":"2026-08-10","note":"Legacy 2016 EPA Health Advisory combined PFOA+PFOS metric. Not a current MCL."},"well_counts":{"active":2,"retired":1,"facilities_synced_at":"2026-10-12T00:17:03.546Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":{"value":0.0465,"compounds_used":["PFHXS","PFBS"],"is_partial":true,"threshold":1,"components":[{"code":"PFHXS","value_ng_l":0.46,"hbwc_ng_l":10,"ratio":0.046},{"code":"PFBS","value_ng_l":0.99,"hbwc_ng_l":2000,"ratio":0.0005}]},"tthm_lraa":[{"monitoring_point":"system_wide","value":33.41,"unit":"ug/L","quarters_used":["2023Q3","2024Q3","2025Q3","2026Q3"],"sample_count":4,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"system_wide","value":5.25,"unit":"ug/L","quarters_used":["2023Q3","2024Q3","2025Q3","2026Q3"],"sample_count":4,"mcl":60,"exceeds_mcl":false}]}