Here is what the EPA's own data shows about tap water in Foss. According to EPA SDWIS data retrieved October 2026, Foss is served by 2 active community water systems, together reported to serve about 139 people.
As of October 2026, EPA records show 159 violations across the community water system(s) serving Foss, going back to the earliest EPA record. 4 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.
Health-based LEAD AND COPPER RULE REVISIONS: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in October 2024. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
Health-based Coliform (Pre-TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times between November 1980 and May 1982. The EPA record lists a level of 10 ; the limit (MCL) is 1 . All have since returned to compliance, per EPA records.
Monitoring Interim Enhanced Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between September 2025 and December 2025. All have since returned to compliance, per EPA records.
Monitoring Chlorine: 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 September 2025. All have since returned to compliance, per EPA records.
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 June 1993 and July 2025. EPA records do not show all of these as returned to compliance.
Monitoring CONDUCTIVITY @ 25 C UMHOS/CM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
Monitoring pH: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
Monitoring Alkalinity, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
Monitoring Temperature (Centigrade): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
Monitoring CALCIUM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2025. EPA records do not show all of these as returned to compliance.
Monitoring Endrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. All have since returned to compliance, per EPA records.
Monitoring Diquat: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2024 and January 2025. All have since returned to compliance, per EPA records.
Monitoring Endothall: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2024 and January 2025. All have since returned to compliance, per EPA records.
Monitoring Glyphosate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. All have since returned to compliance, per EPA records.
Monitoring 1,2-DIBROMO-3-CHLOROPROPANE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. 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 3 times between July 2024 and January 2025. All have since returned to compliance, per EPA records.
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 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 January 2024. 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 once in October 2023. All have since returned to compliance, per EPA records.
Monitoring Gross Alpha, Excl. Radon and U: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.
Monitoring Combined Uranium: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.
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 2008. All have since returned to compliance, per EPA records.
Monitoring Gross Beta Particle Activity: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.
Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 7 times between June 1993 and February 1999. All have since returned to compliance, per EPA records.
Monitoring Coliform (Pre-TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 27 times between December 1979 and January 1987. All have since returned to compliance, per EPA records.
Foss Reservoir Mcd
12 served · surface water · PWSID OK1010829
Monitoring Interim Enhanced Surface Water Treatment Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in February 2021. All have since returned to compliance, per EPA records.
Monitoring Gross Alpha, Excl. Radon and U: 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 Combined Uranium: 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 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 Gross Beta Particle Activity: 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.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved October 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.