Is Katy, TX tap water safe?
The short answer
None of the 15 utilities serving Katy has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Texas’s records.
City of Katy, which serves the most people here, has 3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 24.3 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Katy’s ZIP codes, from EPA’s estimates.
- Open report
City of Katy
Texas · serves 25,253 people · about 2,800 in Katy
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 24.3 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Fort Bend County MUD 58
Texas · serves 10,629 people · about 2,400 in Katy
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 32.3 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Fort Bend County MUD 151
Texas · serves 10,233 people · about 1,800 in Katy
2 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 30.3 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Cinco Southwest MUD 2
Texas · serves 5,496 people · about 1,400 in Katy
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 18.2 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Cimarron MUD
Texas · serves 19,338 people · about 1,300 in Katy
2 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 20.6 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Cinco Southwest MUD 4
Texas · serves 6,093 people · about 1,200 in Katy
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 23.7 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Cinco Southwest MUD 3 Daycare
Texas · serves 5,187 people · about 1,200 in Katy
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 20 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Fort Bend County MUD 35
Texas · serves 6,297 people · about 1,100 in Katy
1 result above the health goal. The worst: Lead at 0.95 ppb, above the health goal.
No health-based violations since 2016
- Open report
Fort Bend County MUD 57
Texas · serves 5,335 people · about 1,100 in Katy
2 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 20.4 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Cinco MUD 14
Texas · serves 6,192 people · about 1,000 in Katy
1 result above EPA’s health benchmark. The worst: Lithium at 21.1 ppb, above EPA’s health benchmark.
No health-based violations since 2016
5 more utilities in Katy
By EPA’s estimate, each serves fewer people in Katy than those above.
- Harris - Fort Bend Counties MUD 3serves 9,297 people · about 1,000 in Katy · no health-based violations since 2016
- Harris Fort Bend Counties MUD 5serves 4,641 people · about 940 in Katy · no health-based violations since 2016
- Fort Bend County MUD 34serves 5,367 people · about 920 in Katy · no health-based violations since 2016
- Harris Fort Bend Counties MUD 1serves 3,812 people · about 820 in Katy · no health-based violations since 2016
- Fort Bend County MUD 182serves 10,498 people · about 780 in Katy · no health-based violations since 2016
MUD stands for municipal utility district, a local water and sewer district common in Texas.
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in City of Katy’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic, Lead
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Water testing near Katy
The 3 labs Texas certifies closest to Katy, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
R&C Joy, Inc.
Katy, TX · about 6 miles
Certified for bacteria
Eurofins EMLab P&K – Houston
Houston, TX · about 16 miles
Certified for bacteria
ALS Laboratory Group, Environmental Services Division – Houston, Texas
Houston, TX · about 17 miles
Certified for lead and copper
Texas Well Owner Network, Texas A&M AgriLife Extension: Well Informed screening events, where well owners bring in water samples to be screened for common contaminants, followed by an hour-long session explaining the results. Upcoming events are on the network's calendar. Trainings, Texas Well Owner Network.
All 80 certified labs for TexasWhich ZIP codes are in Katy: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: TCEQ, drinking water laboratories approved for public water system samples; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Katy
Other towns in Harris County with a page of their own.
What to do next
- Read City of Katy’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water