{"schema_version":"1.2","pwsid":"WI1540112","system_name":"BELOIT CITY OF","city":"BELOIT","state":"WI","population_served":36677,"source_type":"GW","summary":"BELOIT CITY OF serves approximately 36,677 people in BELOIT, 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 Lead (90th Percentile) at 0.0045 mg/L, which is 22.5x the health guideline. Data is drawn from source-level compliance monitoring and covers 2000 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2000-10-25","end":"2026-04-06"},"contaminants_tested":138,"contaminants_detected":20,"exceedances":0,"guideline_exceedances":2,"contaminants":[{"name":"Chlorine (free)","code":"0700","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.68,"unit":"mg/L","sample_date":"2026-04-06","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":"PFHpA (Perfluoroheptanoic Acid)","code":"PFHPA","cas_number":null,"group":"pfas","section":"other_detected","measured_value":0.6,"unit":"ng/L","sample_date":"2024-09-10","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"Fluoride (natural)","code":"FLUORIDE","cas_number":"16984-48-8","group":"inorganics","section":"other_detected","measured_value":0.72,"unit":"mg/L","sample_date":"2026-03-25","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":6,"unit":"mg/L","sample_date":"2026-02-18","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":"Haloacetic Acids (HAA5)","code":"2456","cas_number":null,"group":"dbps","section":"other_detected","measured_value":1.49,"unit":"ug/L","sample_date":"2025-09-03","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":4.74,"unit":"ug/L","sample_date":"2025-09-03","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":0.504,"unit":"ug/L","sample_date":"2025-03-12","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":1.393,"unit":"pCi/L","sample_date":"2025-03-12","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":"Gross Alpha Radiation (excluding Radon and Uranium)","code":"4000_EXCL","cas_number":null,"group":"radionuclides","section":"other_detected","measured_value":7.05,"unit":"pCi/L","sample_date":"2025-03-12","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":"Chlorine (total residual)","code":"0700_TOTAL","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.71,"unit":"mg/L","sample_date":"2023-07-05","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":"Nickel","code":"1036","cas_number":null,"group":"inorganics","section":"other_detected","measured_value":0.0076,"unit":"mg/L","sample_date":"2023-05-02","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":"Atrazine","code":"2050","cas_number":null,"group":"vocs","section":"other_detected","measured_value":0.015,"unit":"ug/L","sample_date":"2023-05-02","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":"Barium","code":"BARIUM","cas_number":"7440-39-3","group":"inorganics","section":"other_detected","measured_value":0.069,"unit":"mg/L","sample_date":"2023-05-02","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":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.0045,"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":76,"unit":"ug/L","sample_date":"2023-08-15","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":"PFBS (Perfluorobutane Sulfonate)","code":"PFBS","cas_number":"375-73-5","group":"pfas","section":"pfas","measured_value":1.2,"unit":"ng/L","sample_date":"2026-03-25","source":"DNR","source_scope":"source_monitoring","health_guideline_value":null,"health_guideline_source":null,"epa_mcl_value":null,"status":"detected","detection_limit":null},{"name":"PFHxS (Perfluorohexane Sulfonate)","code":"PFHXS","cas_number":"355-46-4","group":"pfas","section":"pfas","measured_value":1.1,"unit":"ng/L","sample_date":"2025-03-12","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":"pfas","measured_value":2.2,"unit":"ng/L","sample_date":"2025-03-12","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":1.1,"unit":"ng/L","sample_date":"2025-03-12","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":"PFHxA (Perfluorohexanoic Acid)","code":"PFHXA","cas_number":"307-24-4","group":"pfas","section":"pfas","measured_value":0.82,"unit":"ng/L","sample_date":"2025-03-12","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":"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":{"value":3.3,"unit":"ng/L","sample_date":"2025-03-12","note":"Legacy 2016 EPA Health Advisory combined PFOA+PFOS metric. Not a current MCL."},"well_counts":{"active":7,"retired":4,"facilities_synced_at":"2026-04-11T13:48:07.246Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":{"value":0.1106,"compounds_used":["PFHXS","PFBS"],"is_partial":true,"threshold":1,"components":[{"code":"PFHXS","value_ng_l":1.1,"hbwc_ng_l":10,"ratio":0.11},{"code":"PFBS","value_ng_l":1.2,"hbwc_ng_l":2000,"ratio":0.0006}]},"tthm_lraa":[{"monitoring_point":"system_wide","value":4.74,"unit":"ug/L","quarters_used":["2022Q3","2023Q3","2024Q3","2025Q3"],"sample_count":8,"mcl":80,"exceeds_mcl":false}],"haa5_lraa":[{"monitoring_point":"system_wide","value":1.49,"unit":"ug/L","quarters_used":["2022Q3","2023Q3","2024Q3","2025Q3"],"sample_count":8,"mcl":60,"exceeds_mcl":false}]}