{"schema_version":"1.2","pwsid":"WI7370108","system_name":"SPENCER WATERWORKS","city":"SPENCER","state":"WI","population_served":1848,"source_type":"GW","summary":"SPENCER WATERWORKS serves approximately 1,848 people in SPENCER, Wisconsin. Based on contaminant analyses from DNR, EPA ECHO, 0 contaminants have been measured above federal EPA standards (MCL) and 3 exceed health-based guidelines. The most significant finding is Arsenic at 0.003 mg/L, which is 750x the health guideline. Data is drawn from source-level compliance monitoring and covers 2017 through 2026. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2017-09-30","end":"2026-03-20"},"contaminants_tested":19,"contaminants_detected":16,"exceedances":0,"guideline_exceedances":3,"contaminants":[{"name":"Chlorine (total residual)","code":"0700_TOTAL","cas_number":null,"group":"disinfectants","section":"other_detected","measured_value":0.42,"unit":"mg/L","sample_date":"2026-03-20","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":0.42,"unit":"mg/L","sample_date":"2026-03-20","source":"DNR","source_scope":"source_monitoring","health_guideline_value":4,"health_guideline_source":"EPA 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