Chester tap water, in plain English

• Health-based TTHM: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times between January 2019 and July 2024. The EPA record lists a level of 85.3 UG/L; the limit (MCL) is 80 UG/L. EPA records do not show all of these as returned to compliance.
• Health-based Total Haloacetic Acids (HAA5): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in July 2024. The EPA record lists a level of 61 UG/L; the limit (MCL) is 60 UG/L. EPA records do not show all of these as returned to compliance.
• Monitoring LEAD AND COPPER RULE REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. All have since returned to compliance, per EPA records.
• Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2019. All have since returned to compliance, per EPA records.
• Monitoring Benzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2019. All have since returned to compliance, per EPA records.
• Monitoring Arsenic: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2019. EPA records do not show all of these as returned to compliance.
• Monitoring Sodium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2019. All have since returned to compliance, per EPA records.
• Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2017. All have since returned to compliance, per EPA records.
• Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2017. All have since returned to compliance, per EPA records.
• Monitoring Endrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring BHC-GAMMA: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Methoxychlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Toxaphene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Carbaryl: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Methomyl: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Dalapon: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Di(2-ethylhexyl) adipate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring OXAMYL: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Simazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Di(2-ethylhexyl) phthalate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Picloram: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Dinoseb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Hexachlorocyclopentadiene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Aldicarb sulfoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Aldicarb sulfone: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Metolachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Carbofuran: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Aldicarb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Atrazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring LASSO: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Heptachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring 3-Hydroxycarbofuran: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Heptachlor epoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Dieldrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Butachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Propachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring 2,4-D: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring 2,4,5-TP: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring HEXACHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Benzo(a)pyrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Pentachlorophenol: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Aldrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Total Polychlorinated Biphenyls (PCB): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Dicamba: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Metribuzin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring ETHYLENE DIBROMIDE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
• Monitoring Chlordane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.

• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in April 2025. EPA records do not show all of these as returned to compliance.
• Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2020. EPA records do not show all of these as returned to compliance.

• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2006. All have since returned to compliance, per EPA records.

• Health-based Chloride: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 29 times between April 2008 and July 2022. The EPA record lists a level of 280 MG/L; the limit (MCL) is 250 MG/L. EPA records do not show all of these as returned to compliance.
• Health-based Lead and Copper Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times between January 1996 and December 1999. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Monitoring Iron: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2025. EPA records do not show all of these as returned to compliance.
• Monitoring Manganese: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2025. EPA records do not show all of these as returned to compliance.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between January 2002 and July 2004. All have since returned to compliance, per EPA records.

As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.

• Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2019. All have since returned to compliance, per EPA records.
• Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in September 2016. All have since returned to compliance, per EPA records.
• Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in September 2016. All have since returned to compliance, per EPA records.

• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in December 2025. EPA records do not show all of these as returned to compliance.

• Health-based Iron: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in April 2022. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Health-based contaminant code null: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2021. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between January 2024 and October 2024. EPA records do not show all of these as returned to compliance.
• Monitoring contaminant code null: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between September 2016 and October 2021. All have since returned to compliance, per EPA records.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2004 and January 2012. EPA records do not show all of these as returned to compliance.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2005 and January 2007. All have since returned to compliance, per EPA records.