A86/100
Katy Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 46,813 residents · Texas
What's In Katy's Tap Water?
66
Contaminants Tested
0
Exceed EPA Limits
1
Above EPA Goals
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
1
Violation (last 5yr)
1
Unresolved
0
Health-Related
TIER 3Unresolved
Failed to conduct Level 1 Assessment
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
LANCASTER MUD 1
Population Served
2,685
Water Source
Purchased Surface Water
System ID
TX0570176
FORT BEND COUNTY MUD 5
Population Served
4,665
Water Source
Groundwater
System ID
TX0790482
CITY OF KATY
Population Served
25,253
Water Source
Groundwater
System ID
TX1010017
MASON CREEK UTILITY DISTRICT
Population Served
8,900
Water Source
Groundwater
System ID
TX1010379
KAUFMAN COUNTY MUD 10
Population Served
2,901
Water Source
Purchased Surface Water
System ID
TX1290054
MONTGOMERY COUNTY MUD 137
Population Served
2,409
Water Source
Groundwater
System ID
TX1700840
Frequently Asked Questions About Katy Water
Is Katy tap water safe to drink?
Katy, Texas tap water receives a grade of A (86/100), which is considered excellent. Out of 66 contaminants tested, none exceed EPA maximum contaminant levels (MCLs) and 1 exceed health guidelines (MCLGs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Katy's water?
Of the 66 contaminants tested in Katy's water supply, the most notable include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.
Does Katy have any water quality violations?
Yes, Katy has 48 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, MON, Other. 4 of these are health-based violations, which are the most serious category.
Do I need a water filter in Katy?
Katy water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 1 contaminant(s) exceed these stricter goals.
Where does Katy's tap water come from?
Katy's drinking water is sourced from purchased surface water and supplied by LANCASTER MUD 1 and 5 other water system(s). The system serves approximately 46,813 people. Surface water sources include rivers, lakes, and reservoirs.
How often is Katy's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Katy's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Katy's water compare to other cities in Texas?
Katy's water quality score of 86/100 earns a grade of A, which is considered excellent. This places Katy among the better-performing water systems in Texas. Visit our Texas state page to see how all cities in the state compare.
What should I do if I'm concerned about Katy's water quality?
If you have concerns about Katy's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (LANCASTER MUD 1) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.