TX / Katy
TX · Tap water records
Katy tap water, in plain English
Here is what the EPA's own data shows about tap water in Katy. According to EPA SDWIS data retrieved June 2026, Katy is served by 9 active community water systems, together reported to serve about 44,722 people.
As of June 2026, EPA records show 304 violations across the community water system(s) serving Katy, going back to the earliest EPA record. 44 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.
What the EPA has on record, by system
City Of Katy
25,253 served · groundwater · PWSID TX1010017 - Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in June 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 2 times in July 2019. All have since returned to compliance, per EPA records.
Mason Creek Utility District
8,900 served · groundwater · PWSID TX1010379 - 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 December 2013 and December 2019. 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 once in April 2017. All have since returned to compliance, per EPA records.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between February 2014 and February 2016. All have since returned to compliance, per EPA records.
Fort Bend County Mud 5
4,665 served · groundwater · PWSID TX0790482 - 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 December 2014. All have since returned to compliance, per EPA records.
Lancaster Mud 1
2,685 served · surface water · PWSID TX0570176 - Health-based Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in July 2016. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between July 2008 and August 2016. 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 2 times between October 2012 and October 2013. All have since returned to compliance, per EPA records.
Montgomery County Mud 137
2,409 served · groundwater · PWSID TX1700840 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.
Waller County Mud 35
411 served · groundwater · PWSID TX2370145 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.
Northern Hills Water Service
264 served · surface water · PWSID TX0910126 - Health-based Chloramine: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times in July 2021. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 38 times between February 2014 and February 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 65 times between October 2019 and February 2023. 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 22 times between October 2015 and January 2023. 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 20 times between July 2019 and October 2022. EPA records do not show all of these as returned to compliance.
- Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 10 times between October 2016 and July 2021. 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 10 times between October 2016 and July 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 18 times between January 2007 and July 2020. All have since returned to compliance, per EPA records.
- Monitoring Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2020. 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 2020. All have since returned to compliance, per EPA records.
Chanticor Series
90 served · groundwater · PWSID TX1700727 - Health-based Lead and Copper Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 4 times between October 2017 and October 2023. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
- Health-based Gross Alpha, Excl. Radon and U: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 18 times between October 2011 and January 2016. The EPA record lists a level of 31 PCI/L; the limit (MCL) is 15 PCI/L. All have since returned to compliance, per EPA records.
- Health-based Combined Radium (-226 and -228): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 17 times between October 2011 and October 2015. The EPA record lists a level of 8 PCI/L; the limit (MCL) is 5 PCI/L. 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 34 times between December 2013 and March 2024. All have since returned to compliance, per EPA records.
- Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 19 times between June 2012 and November 2023. 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 2 times between July 2012 and July 2015. All have since returned to compliance, per EPA records.
August Lakes Wsc
45 served · groundwater · PWSID TX2370114 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.
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 June 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.