{"schema_version":"1.2","pwsid":"IL1515050","system_name":"MILLSTONE PWD","city":"NASHVILLE","state":"IL","population_served":5565,"source_type":"GW","summary":"MILLSTONE PWD serves approximately 5,565 people in NASHVILLE, Illinois. Based on contaminant analyses from 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 2 contaminants. 1 contaminant exceeds health-based guidelines. The most significant finding is Lead (90th Percentile) at 0.00411 mg/L, which is 20.5x the health guideline. Data is drawn from source-level compliance monitoring and covers 2017 through 2025. Results reflect conditions at the point of collection (wells, treatment plants), not necessarily at the tap.","data_period":{"start":"2017-06-30","end":"2025-12-31"},"contaminants_tested":31,"contaminants_detected":1,"exceedances":0,"guideline_exceedances":1,"contaminants":[{"name":"Lead (90th Percentile)","code":"PB90","cas_number":"7439-92-1","group":"lead_copper","section":"guideline_exceedance","measured_value":0.00411,"unit":"mg/L","sample_date":"2025-12-31","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}],"sources":[{"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":null,"well_counts":{"active":3,"retired":5,"facilities_synced_at":"2026-09-06T14:49:36.593Z"},"historical_wells":[],"has_only_historical_data":false,"pfas_hazard_index":null,"tthm_lraa":[],"haa5_lraa":[]}