What was found in Katy's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Fluoride | 440 µg/L 11% of the EPA limit 4000 µg/L Main supplier: CITY OF KATY · 25,253 people · 2018
Highest in the city: 575 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2017 | 2/2 | SYR4 |
| Copper | 187.99999999999997 µg/L 14% of the EPA limit 1300 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019
Highest in the city: 318.9999999999992 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2019 | 2/2 | SYR4 |
| Barium | 187.85 µg/L 9.4% of the EPA limit 2000 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019
Highest in the city: 240 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2017 | 2/2 | SYR4 |
| Lithium | 24.3 µg/L No EPA limit set Main supplier: CITY OF KATY · 25,253 people · 2024
Highest in the city: 36 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2024 | 2/2 | UCMR-5 |
| Nitrate | 30 µg/L 0.3% of the EPA limit 10000 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Nitrate-Nitrite | 28.499999999999996 µg/L 0.3% of the EPA limit 10000 µg/L Main supplier: CITY OF KATY · 25,253 people · 2015 | 2/2 | SYR4 |
| Lead | 8.079999999999998 µg/L 54% of the EPA limit 15 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019
Highest in the city: 17.799999999999983 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2019 | 2/2 | SYR4 |
| Combined Uranium | 13.049999999999999 µg/L 43% of the EPA limit 30 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Gross Alpha, Excl. Radon And U | 11.75 pCi/L 78% of the EPA limit 15 pCi/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Xylenes, Total | 8.289999999999996 µg/L 0.1% of the EPA limit 10000 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 1/2 | SYR4 |
| Arsenic | 3.5 µg/L 35% of the EPA limit 10 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019
Highest in the city: 7.5 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2017 | 2/2 | SYR4 |
| Gross Beta Particle Activity | 7.439999999999999 pCi/L No EPA limit set Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Selenium | 7.25 µg/L 14% of the EPA limit 50 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Combined Radium (-226 And -228) | 2.13 pCi/L 43% of the EPA limit 5 pCi/L Main supplier: CITY OF KATY · 25,253 people · 2019
Highest in the city: 2.7889999999999997 pCi/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2019 | 2/2 | SYR4 |
| TTHM | 2.7399999999999993 µg/L 3.4% of the EPA limit 80 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Bromoform | 1.9749999999999992 µg/L No EPA limit set Main supplier: CITY OF KATY · 25,253 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 1.56 µg/L No EPA limit set Main supplier: CITY OF KATY · 25,253 people · 2019
Highest in the city: 1.64 µg/L — MASON CREEK UTILITY DISTRICT · 8,900 people · 2019 | 2/2 | SYR4 |
| Ethylbenzene | 1.42 µg/L 0.2% of the EPA limit 700 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 1/2 | SYR4 |
| Dibromoacetic Acid | 1.2 µg/L No EPA limit set Main supplier: CITY OF KATY · 25,253 people · 2019 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 1.2 µg/L 2% of the EPA limit 60 µg/L Main supplier: CITY OF KATY · 25,253 people · 2019 | 1/2 | SYR4 |
| Lead | 0.0027 mg/L 18% of the EPA limit 0.0150 mg/L Main supplier: CITY OF KATY · 25,253 people · 2023 | 2/2 | LCR |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Katy
| Supplier | Population served |
|---|---|
| CITY OF KATY | 25,253 |
| MASON CREEK UTILITY DISTRICT | 8,900 |
Frequently asked questions about Katy tap water
Is Katy tap water safe to drink?
EPA testing detected 21 contaminants in the water serving Katy. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Katy?
2 public water suppliers report drinking-water monitoring for Katy, Texas to the EPA. Each is listed above with its population served.
What contaminants are in Katy's water?
The contaminants EPA monitoring detected in Katy include Fluoride, Copper, Barium, Lithium, Nitrate. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.