California · drinking water · SDWIS through latest publish

Madison Service Dist Water Quality — Madison, California

PWSID CA5700571 · GroundwaterMunicipal

876 people served. 1 health-based SDWIS violation recorded in the past 5 years. 151 remain unresolved. Last cited 1 year ago.

ALL SDWIS VIOLATIONS · 20202026 (annual count)
Bar chart of annual values from 2020 to 2026, in violations. Most recent year (2026): 0 violations.74 violations'20'21'22'23'24'25'260 violations
Anomaly engine

Active signals

UNRESOLVED VIOLATION · SDWIS VIOLATION

Contaminant 1002

Unresolved Lead and Copper Rule violation cited in 2025 (contaminant 1002).

EPA SDWIS record

UNRESOLVED VIOLATION · SDWIS VIOLATION

Arsenic

Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (arsenic).

EPA SDWIS record

UNRESOLVED VIOLATION · SDWIS VIOLATION

Barium

Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (barium).

EPA SDWIS record

UNRESOLVED VIOLATION · SDWIS VIOLATION

Cadmium

Unresolved Phase I/II/V Inorganic Chemical Rules violation cited in 2025 (cadmium).

EPA SDWIS record

Most-cited contaminants

What This Utility Gets Cited For

  • Contaminant 80004 citations
  • Cyanide3 citations
  • Contaminant 10022 citations
  • Arsenic2 citations
  • Barium2 citations
  • Cadmium2 citations
Violation history

What's On The SDWIS Record

Health-based violations exceed an MCL or treatment-technique standard. Monitoring violations are reporting failures with no measured exceedance — they tell you the system isn't fully transparent, not that the water is unsafe today.

MONITORING · CONTAMINANT 1002UNRESOLVED

2025 · Contaminant 1002 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 1002

MONITORING · ARSENICUNRESOLVED

2025 · Arsenic · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1005

MONITORING · BARIUMUNRESOLVED

2025 · Barium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1010

MONITORING · CADMIUMUNRESOLVED

2025 · Cadmium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1015

MONITORING · CHROMIUMUNRESOLVED

2025 · Chromium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1020

MONITORING · MERCURY (INORGANIC)UNRESOLVED

2025 · Mercury (inorganic) · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1025

MONITORING · SELENIUMUNRESOLVED

2025 · Selenium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1035

MONITORING · CONTAMINANT 1036UNRESOLVED

2025 · Contaminant 1036 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1036

MONITORING · CYANIDEUNRESOLVED

2025 · Cyanide · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1041

MONITORING · CONTAMINANT 1074UNRESOLVED

2025 · Contaminant 1074 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1074

MONITORING · CONTAMINANT 1075UNRESOLVED

2025 · Contaminant 1075 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1075

MONITORING · CONTAMINANT 1085UNRESOLVED

2025 · Contaminant 1085 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1085

MONITORING · ASBESTOSUNRESOLVED

2025 · Asbestos · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1045

MONITORING · CONTAMINANT 1039UNRESOLVED

2025 · Contaminant 1039 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 1039

MONITORING · CONTAMINANT 2218UNRESOLVED

2025 · Contaminant 2218 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2218

MONITORING · CONTAMINANT 2251UNRESOLVED

2025 · Contaminant 2251 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2251

MONITORING · XYLENES (TOTAL)UNRESOLVED

2025 · Xylenes (total) · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2378

MONITORING · BENZENEUNRESOLVED

2025 · Benzene · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2380

MONITORING · CONTAMINANT 2413UNRESOLVED

2025 · Contaminant 2413 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2413

MONITORING · CONTAMINANT 2904UNRESOLVED

2025 · Contaminant 2904 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2904

MONITORING · CONTAMINANT 2955UNRESOLVED

2025 · Contaminant 2955 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2955

MONITORING · CONTAMINANT 2964UNRESOLVED

2025 · Contaminant 2964 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2964

MONITORING · CONTAMINANT 2968UNRESOLVED

2025 · Contaminant 2968 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2968

MONITORING · CONTAMINANT 2969UNRESOLVED

2025 · Contaminant 2969 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2969

MONITORING · CONTAMINANT 2976UNRESOLVED

2025 · Contaminant 2976 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2976

MONITORING · CONTAMINANT 2977UNRESOLVED

2025 · Contaminant 2977 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2977

MONITORING · CONTAMINANT 2978UNRESOLVED

2025 · Contaminant 2978 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2978

MONITORING · CONTAMINANT 2979UNRESOLVED

2025 · Contaminant 2979 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2979

MONITORING · METHYL TERT-BUTYL ETHER (MTBE)UNRESOLVED

2025 · Methyl tert-butyl ether (MTBE) · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2980

MONITORING · CONTAMINANT 2981UNRESOLVED

2025 · Contaminant 2981 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2981

MONITORING · CONTAMINANT 2982UNRESOLVED

2025 · Contaminant 2982 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2982

MONITORING · CONTAMINANT 2983UNRESOLVED

2025 · Contaminant 2983 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2983

MONITORING · CONTAMINANT 2984UNRESOLVED

2025 · Contaminant 2984 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2984

MONITORING · CONTAMINANT 2985UNRESOLVED

2025 · Contaminant 2985 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2985

MONITORING · CONTAMINANT 2987UNRESOLVED

2025 · Contaminant 2987 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2987

MONITORING · CONTAMINANT 2988UNRESOLVED

2025 · Contaminant 2988 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2988

MONITORING · CONTAMINANT 2989UNRESOLVED

2025 · Contaminant 2989 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2989

MONITORING · CONTAMINANT 2990UNRESOLVED

2025 · Contaminant 2990 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2990

MONITORING · CONTAMINANT 2991UNRESOLVED

2025 · Contaminant 2991 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2991

MONITORING · CONTAMINANT 2992UNRESOLVED

2025 · Contaminant 2992 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2992

MONITORING · CONTAMINANT 2996UNRESOLVED

2025 · Contaminant 2996 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2996

MONITORING · ENDRINUNRESOLVED

2025 · Endrin · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2005

MONITORING · LINDANEUNRESOLVED

2025 · Lindane · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2010

MONITORING · METHOXYCHLORUNRESOLVED

2025 · Methoxychlor · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2015

MONITORING · TOXAPHENEUNRESOLVED

2025 · Toxaphene · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2020

MONITORING · CONTAMINANT 2031UNRESOLVED

2025 · Contaminant 2031 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2031

MONITORING · CONTAMINANT 2032UNRESOLVED

2025 · Contaminant 2032 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2032

MONITORING · CONTAMINANT 2033UNRESOLVED

2025 · Contaminant 2033 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2033

MONITORING · CONTAMINANT 2034UNRESOLVED

2025 · Contaminant 2034 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2034

MONITORING · CONTAMINANT 2035UNRESOLVED

2025 · Contaminant 2035 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2035

MONITORING · CONTAMINANT 2036UNRESOLVED

2025 · Contaminant 2036 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2036

MONITORING · CONTAMINANT 2037UNRESOLVED

2025 · Contaminant 2037 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2037

MONITORING · CONTAMINANT 2039UNRESOLVED

2025 · Contaminant 2039 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2039

MONITORING · CONTAMINANT 2040UNRESOLVED

2025 · Contaminant 2040 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2040

MONITORING · CONTAMINANT 2041UNRESOLVED

2025 · Contaminant 2041 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2041

MONITORING · CONTAMINANT 2042UNRESOLVED

2025 · Contaminant 2042 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2042

MONITORING · CONTAMINANT 2046UNRESOLVED

2025 · Contaminant 2046 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2046

MONITORING · 2,4-DUNRESOLVED

2025 · 2,4-D · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2050

MONITORING · CONTAMINANT 2051UNRESOLVED

2025 · Contaminant 2051 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2051

MONITORING · CONTAMINANT 2063UNRESOLVED

2025 · Contaminant 2063 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2063

MONITORING · 2,4,5-TP (SILVEX)UNRESOLVED

2025 · 2,4,5-TP (Silvex) · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2065

MONITORING · CONTAMINANT 2067UNRESOLVED

2025 · Contaminant 2067 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2067

MONITORING · ALACHLORUNRESOLVED

2025 · Alachlor · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2105

MONITORING · ATRAZINEUNRESOLVED

2025 · Atrazine · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2110

MONITORING · CONTAMINANT 2274UNRESOLVED

2025 · Contaminant 2274 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2274

MONITORING · CARBOFURANUNRESOLVED

2025 · Carbofuran · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2306

MONITORING · CONTAMINANT 2326UNRESOLVED

2025 · Contaminant 2326 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2326

MONITORING · TRICHLOROETHYLENE (TCE)UNRESOLVED

2025 · Trichloroethylene (TCE) · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2383

MONITORING · CONTAMINANT 2931UNRESOLVED

2025 · Contaminant 2931 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2931

MONITORING · CONTAMINANT 2946UNRESOLVED

2025 · Contaminant 2946 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2946

MONITORING · CONTAMINANT 2959UNRESOLVED

2025 · Contaminant 2959 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2959

MONITORING · CONTAMINANT 2625UNRESOLVED

2025 · Contaminant 2625 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2625

MONITORING · CONTAMINANT 2626UNRESOLVED

2025 · Contaminant 2626 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2626

MONITORING · CONTAMINANT 2727UNRESOLVED

2025 · Contaminant 2727 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2727

MONITORING · CONTAMINANT 8000

2024 · Contaminant 8000 · Revised Total Coliform Rule

Monitoring failure; returned to compliance

CONTAMINANT CODE 8000

MONITORING · CONTAMINANT 8000UNRESOLVED

2024 · Contaminant 8000 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 8000

MONITORING · CONTAMINANT 8000

2024 · Contaminant 8000 · Lead and Copper Rule

Failure to monitor as scheduled; returned to compliance

CONTAMINANT CODE 8000

MONITORING · CONTAMINANT 8000

2024 · Contaminant 8000 · Revised Total Coliform Rule

Monitoring failure; returned to compliance

CONTAMINANT CODE 8000

HEALTH-BASED · CONTAMINANT 5200UNRESOLVED

2024 · Contaminant 5200 · Phase I/II/V Inorganic Chemical Rules

Treatment technique violation

CONTAMINANT CODE 5200

MONITORING · CONTAMINANT 5200UNRESOLVED

2024 · Contaminant 5200 · Phase I/II/V Inorganic Chemical Rules

Reporting failure

CONTAMINANT CODE 5200

MONITORING · CONTAMINANT 2218UNRESOLVED

2023 · Contaminant 2218 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2218

MONITORING · CONTAMINANT 2251UNRESOLVED

2023 · Contaminant 2251 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2251

MONITORING · XYLENES (TOTAL)UNRESOLVED

2023 · Xylenes (total) · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2378

MONITORING · BENZENEUNRESOLVED

2023 · Benzene · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2380

MONITORING · CONTAMINANT 2413UNRESOLVED

2023 · Contaminant 2413 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2413

MONITORING · CONTAMINANT 2904UNRESOLVED

2023 · Contaminant 2904 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2904

MONITORING · CONTAMINANT 2955UNRESOLVED

2023 · Contaminant 2955 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2955

MONITORING · CONTAMINANT 2964UNRESOLVED

2023 · Contaminant 2964 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2964

MONITORING · CONTAMINANT 2968UNRESOLVED

2023 · Contaminant 2968 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2968

MONITORING · CONTAMINANT 2969UNRESOLVED

2023 · Contaminant 2969 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2969

MONITORING · CONTAMINANT 2976UNRESOLVED

2023 · Contaminant 2976 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2976

MONITORING · CONTAMINANT 2977UNRESOLVED

2023 · Contaminant 2977 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2977

MONITORING · CONTAMINANT 2978UNRESOLVED

2023 · Contaminant 2978 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2978

MONITORING · CONTAMINANT 2979UNRESOLVED

2023 · Contaminant 2979 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2979

MONITORING · METHYL TERT-BUTYL ETHER (MTBE)UNRESOLVED

2023 · Methyl tert-butyl ether (MTBE) · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2980

MONITORING · CONTAMINANT 2981UNRESOLVED

2023 · Contaminant 2981 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2981

MONITORING · CONTAMINANT 2982UNRESOLVED

2023 · Contaminant 2982 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2982

MONITORING · CONTAMINANT 2983UNRESOLVED

2023 · Contaminant 2983 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2983

MONITORING · CONTAMINANT 2984UNRESOLVED

2023 · Contaminant 2984 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2984

MONITORING · CONTAMINANT 2985UNRESOLVED

2023 · Contaminant 2985 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2985

MONITORING · CONTAMINANT 2987UNRESOLVED

2023 · Contaminant 2987 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2987

MONITORING · CONTAMINANT 2988UNRESOLVED

2023 · Contaminant 2988 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2988

MONITORING · CONTAMINANT 2989UNRESOLVED

2023 · Contaminant 2989 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2989

MONITORING · CONTAMINANT 2990UNRESOLVED

2023 · Contaminant 2990 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2990

MONITORING · CONTAMINANT 2991UNRESOLVED

2023 · Contaminant 2991 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2991

MONITORING · CONTAMINANT 2992UNRESOLVED

2023 · Contaminant 2992 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2992

MONITORING · CONTAMINANT 2996UNRESOLVED

2023 · Contaminant 2996 · Arsenic Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2996

MONITORING · ENDRINUNRESOLVED

2023 · Endrin · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2005

MONITORING · LINDANEUNRESOLVED

2023 · Lindane · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2010

MONITORING · METHOXYCHLORUNRESOLVED

2023 · Methoxychlor · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2015

MONITORING · TOXAPHENEUNRESOLVED

2023 · Toxaphene · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2020

MONITORING · CONTAMINANT 2031UNRESOLVED

2023 · Contaminant 2031 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2031

MONITORING · CONTAMINANT 2032UNRESOLVED

2023 · Contaminant 2032 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2032

MONITORING · CONTAMINANT 2033UNRESOLVED

2023 · Contaminant 2033 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2033

MONITORING · CONTAMINANT 2034UNRESOLVED

2023 · Contaminant 2034 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2034

MONITORING · CONTAMINANT 2035UNRESOLVED

2023 · Contaminant 2035 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2035

MONITORING · CONTAMINANT 2036UNRESOLVED

2023 · Contaminant 2036 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2036

MONITORING · CONTAMINANT 2037UNRESOLVED

2023 · Contaminant 2037 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2037

MONITORING · CONTAMINANT 2039UNRESOLVED

2023 · Contaminant 2039 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2039

MONITORING · CONTAMINANT 2040UNRESOLVED

2023 · Contaminant 2040 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2040

MONITORING · CONTAMINANT 2041UNRESOLVED

2023 · Contaminant 2041 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2041

MONITORING · CONTAMINANT 2042UNRESOLVED

2023 · Contaminant 2042 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2042

MONITORING · CONTAMINANT 2046UNRESOLVED

2023 · Contaminant 2046 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2046

MONITORING · 2,4-DUNRESOLVED

2023 · 2,4-D · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2050

MONITORING · CONTAMINANT 2051UNRESOLVED

2023 · Contaminant 2051 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2051

MONITORING · CONTAMINANT 2063UNRESOLVED

2023 · Contaminant 2063 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2063

MONITORING · 2,4,5-TP (SILVEX)UNRESOLVED

2023 · 2,4,5-TP (Silvex) · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2065

MONITORING · CONTAMINANT 2067UNRESOLVED

2023 · Contaminant 2067 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2067

MONITORING · ALACHLORUNRESOLVED

2023 · Alachlor · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2105

MONITORING · ATRAZINEUNRESOLVED

2023 · Atrazine · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2110

MONITORING · CONTAMINANT 2274UNRESOLVED

2023 · Contaminant 2274 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2274

MONITORING · CARBOFURANUNRESOLVED

2023 · Carbofuran · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2306

MONITORING · CONTAMINANT 2326UNRESOLVED

2023 · Contaminant 2326 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2326

MONITORING · TRICHLOROETHYLENE (TCE)UNRESOLVED

2023 · Trichloroethylene (TCE) · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2383

MONITORING · CONTAMINANT 2931UNRESOLVED

2023 · Contaminant 2931 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2931

MONITORING · CONTAMINANT 2946UNRESOLVED

2023 · Contaminant 2946 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2946

MONITORING · CONTAMINANT 2959UNRESOLVED

2023 · Contaminant 2959 · Nitrate/Nitrite

Failure to monitor as scheduled

CONTAMINANT CODE 2959

MONITORING · CONTAMINANT 2625UNRESOLVED

2023 · Contaminant 2625 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2625

MONITORING · CONTAMINANT 2626UNRESOLVED

2023 · Contaminant 2626 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2626

MONITORING · CONTAMINANT 2727UNRESOLVED

2023 · Contaminant 2727 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 2727

MONITORING · CONTAMINANT 1002UNRESOLVED

2023 · Contaminant 1002 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 1002

MONITORING · ARSENICUNRESOLVED

2023 · Arsenic · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1005

MONITORING · BARIUMUNRESOLVED

2023 · Barium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1010

MONITORING · CADMIUMUNRESOLVED

2023 · Cadmium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1015

MONITORING · CHROMIUMUNRESOLVED

2023 · Chromium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1020

MONITORING · MERCURY (INORGANIC)UNRESOLVED

2023 · Mercury (inorganic) · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1025

MONITORING · SELENIUMUNRESOLVED

2023 · Selenium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1035

MONITORING · CONTAMINANT 1036UNRESOLVED

2023 · Contaminant 1036 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1036

MONITORING · CYANIDEUNRESOLVED

2023 · Cyanide · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1041

MONITORING · CONTAMINANT 1074UNRESOLVED

2023 · Contaminant 1074 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1074

MONITORING · CONTAMINANT 1075UNRESOLVED

2023 · Contaminant 1075 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1075

MONITORING · CONTAMINANT 1085UNRESOLVED

2023 · Contaminant 1085 · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1085

MONITORING · ASBESTOSUNRESOLVED

2023 · Asbestos · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled

CONTAMINANT CODE 1045

MONITORING · CONTAMINANT 1039UNRESOLVED

2023 · Contaminant 1039 · Lead and Copper Rule

Failure to monitor as scheduled

CONTAMINANT CODE 1039

MONITORING · BERYLLIUM

2020 · Beryllium · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled; returned to compliance

CONTAMINANT CODE 1040

MONITORING · CYANIDE

2020 · Cyanide · Phase I/II/V Inorganic Chemical Rules

Failure to monitor as scheduled; returned to compliance

CONTAMINANT CODE 1041

Equity context · ACS 2018-2022 · USEPA-clone EJ disparity

Who Drinks This Water

Yolo County, California (utility's served county per SDWIS GEOGRAPHIC_AREA — city-level not yet matched): a service population of 217,141. Local disparity score for pm2.5 (fine particulate) sits well above the reference burden (158). Why we surface this →

POPULATION SHARE
17.4%

Low-income

POPULATION SHARE
55.7%

People of color

POPULATION SHARE
5.6%

Under age 5

POPULATION SHARE
13.0%

Over age 64

NATIONAL PERCENTILE · vs all US block groups (population-weighted; ranked against the national EJScreen indicator distribution)

  • PM2.5 (fine particulate)Health riskFine inhalable particles 2.5 micrometers or smaller. They travel deep into the lungs and into the bloodstream — linked to asthma, heart disease, stroke, and premature death.96in the highest 5% nationally
  • OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.66above the national median
  • Nitrogen dioxide (NO₂)Health riskA tailpipe and combustion gas. Concentrates near busy roads and industrial sites; raises risk of airway inflammation, asthma, and lower respiratory infections in children.61above the national median
  • Diesel particulateHealth riskSoot from diesel engines (trucks, trains, ports, construction). EPA classifies it as a likely human carcinogen and a major driver of childhood asthma near freight corridors.61above the national median
  • Toxic releases (RSEI)Health riskEPA's Risk-Screening Environmental Indicators score — weights TRI chemical releases by toxicity, where they go, and how many people are nearby. Higher means greater modeled cancer and chronic-health risk.28below the national median
  • Traffic proximityHealth riskPopulation-weighted distance to high-volume roads. Living close to heavy traffic raises exposure to PM2.5, NO₂, and diesel exhaust — and the cardiovascular and asthma risks that follow.69above the national median
  • Lead-paint risk (pre-1960 housing)Health riskShare of housing built before 1960, when lead-based paint was common. Dust from deteriorating paint is the leading cause of childhood lead poisoning, which permanently impairs cognitive development.51near the national median
  • Superfund site proximityHealth riskPopulation-weighted distance to NPL Superfund sites — the most contaminated waste sites in the country. Nearby groundwater, soil, and air can carry industrial solvents, metals, and other long-lived contaminants.75above the national median
  • RMP-facility proximityHealth riskDistance to facilities holding chemicals at quantities large enough to require an EPA Risk Management Plan (refineries, fertilizer plants, etc.). These pose acute exposure risk during accidental releases.60near the national median
  • Hazardous-waste site proximityHealth riskDistance to RCRA hazardous-waste handlers (treatment, storage, disposal facilities). Indicates potential exposure to industrial chemicals in air, soil, and groundwater.77above the national median
  • Underground storage tanksHealth riskDensity of underground tanks (gasoline, heating oil, industrial fluids). Leaking tanks are a leading source of benzene and other volatile organic compounds in groundwater drinking-water supplies.28below the national median
  • NPDES wastewater proximityHealth riskDistance to permitted industrial wastewater dischargers. Closer proximity raises exposure to pollutants released into surface waters used for fishing, recreation, and downstream drinking-water intakes.76above the national median
  • Drinking-water non-complianceHealth riskEPA score for public water systems with health-based Safe Drinking Water Act violations. Higher means more residents on systems that recently exceeded safe limits for contaminants like lead, arsenic, or nitrate.78above the national median
EJ disparity scores · service-area block groups (100 = national reference; higher = greater disparate burden)
IndicatorDisparity scoreReading
PM2.5 (fine particulate)158well above the reference burden
Ozone125moderately above the reference
Nitrogen dioxide (NO₂)100near the reference
Diesel particulate95near the reference
Toxic releases (RSEI)37well below the reference
Traffic proximity100near the reference
Lead-paint risk (pre-1960 housing)58below the reference
Superfund site proximity57below the reference
RMP-facility proximity89below the reference
Hazardous-waste site proximity116moderately above the reference
Underground storage tanks0well below the reference
NPDES wastewater proximity55below the reference
Drinking-water non-compliance2well below the reference

Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror).

Source. EPA Safe Drinking Water Information System · retrieved 2026-05-07. Reporting period 2020-01-012026-05-07.

What this is not. SDWIS records compliance against federal MCLs — not a direct readout of tap-water concentrations. Active health-based violations are not the same as a current crisis; we link to the EPA record so you can verify return-to-compliance status before forming a conclusion.