Tap Water Quality Report
Tap water quality in ROUND ROCK, Texas
Tap water in ROUND ROCK, Texas receives a grade of C (70/100) from TapWaterSafety.org. It's served by CITY OF ROUND ROCK. The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Bromochloroacetic acid significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in ROUND ROCK's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving ROUND ROCK.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 27.3 ppb, 454x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 47.9 ppb, 319x above the EWG health guideline of 0.15 ppb.
Bromochloroacetic acid significantly above health guideline
Moderate concernBromochloroacetic acid detected at 4.98 ppb, 249x above the EWG health guideline of 0.02 ppb.
EPA compliance record
Official U.S. EPA records for CITY OF ROUND ROCK (system ID TX2460003) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for ROUND ROCK
Filters matched to the specific contaminants in ROUND ROCK's water supply.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in ROUND ROCK's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
27.3 ppb | 0.06 | — | — | — | — | — | 454× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
47.9 ppb | 0.15 | 80.0 | 100 | — | — | — | 319× over |
| Bromochloroacetic acid Disinfection byproduct |
4.98 ppb | 0.02 | — | — | — | — | — | 249× over |
| Dibromochloromethane Disinfection byproduct |
20.3 ppb | 0.1 | — | — | — | — | — | 203× over |
| Dibromoacetic acid Disinfection byproduct |
5.91 ppb | 0.03 | — | — | — | — | — | 197× over |
| Bromodichloromethane Disinfection byproduct |
11.8 ppb | 0.06 | — | — | — | — | — | 196× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
10.3 ppb | 0.1 | 60.0 | 60 | — | — | — | 103× over |
| Bromoform Disinfection byproduct |
9.95 ppb | 0.5 | — | — | — | — | — | 20× over |
| Dichloroacetic acid Disinfection byproduct |
3.28 ppb | 0.2 | — | — | — | — | — | 16× over |
| Nitrate and nitrite Inorganic |
1.8 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 13× over |
| Chloroform Disinfection byproduct |
4.15 ppb | 0.4 | — | — | — | — | — | 10× over |
| Radium, combined (-226 and -228) Radiological |
0.5 pCi/L | 0.05 | 5.0 | — | — | — | — | 10× over |
| Trichloroacetic acid Disinfection byproduct |
0.986 ppb | 0.1 | — | — | — | — | — | 9.9× over |
| Nitrate Inorganic |
0.324 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.3× over |
| Chromium (hexavalent) Heavy metal |
0.0394 ppb | 0.02 | — | — | — | — | — | 2.0× over |
| Bromochloromethane Other |
0.0277 ppb | 0.06 | — | — | — | — | — | Below guideline |
| Atrazine Pesticide/Herbicide |
0.0325 ppb | 0.1 | 3.0 | 0.1 | 100 | 0.15 | — | Below guideline |
| Aluminum Heavy metal |
109.1 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Vanadium Other |
2.22 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
39.4 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Chlorate Disinfection byproduct |
10.6 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
1.83 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.238 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.0458 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.0635 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.605 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Cyanide Inorganic |
72.5 ppb | — | 200.0 | 50 | 70 | 150 | — | Fails EU |
| Fluoride Inorganic |
0.245 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Hexadecanoic acid Other |
3.3 ppb | — | — | — | — | — | — | Below guideline |
| Octadecanoic acid Other |
70.0 ppb | — | — | — | — | — | — | Below guideline |
| Phenol, p-tert-butyl- Other |
3.0 ppb | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from CITY OF ROUND ROCK.