Tap Water Quality Report
Tap water quality in HAWTHORNE, California
Tap water in HAWTHORNE, California receives a grade of D (67/100) from TapWaterSafety.org. It's served by GSWC - SOUTHWEST. The most significant water quality concerns are: Haloacetic acids (HAA5) significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Arsenic detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in HAWTHORNE's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving HAWTHORNE.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 36.2 ppb, 362x above the EWG health guideline of 0.1 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 15.1 ppb, 252x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 28.0 ppb, 186x above the EWG health guideline of 0.15 ppb.
Arsenic detected
Moderate concernArsenic detected at 0.446 ppb.
Recommended filters for HAWTHORNE
Filters matched to the specific contaminants in HAWTHORNE's water supply.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Reverse Osmosis
$249-$750Arsenic is most effectively removed by reverse osmosis. Some specialized adsorptive filters also work.
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 HAWTHORNE'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 (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
15.1 ppb | 0.06 | — | — | — | — | — | 252× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
28.0 ppb | 0.15 | 80.0 | 100 | — | — | — | 186× over |
| Bromodichloromethane Disinfection byproduct |
7.33 ppb | 0.06 | — | — | — | — | — | 122× over |
| Arsenic Heavy metal |
0.446 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 112× over |
| Dibromochloromethane Disinfection byproduct |
8.98 ppb | 0.1 | — | — | — | — | — | 90× over |
| Dibromoacetic acid Disinfection byproduct |
1.76 ppb | 0.03 | — | — | — | — | — | 59× over |
| Chloroform Disinfection byproduct |
6.94 ppb | 0.4 | — | — | — | — | — | 17× over |
| Trichloroacetic acid Disinfection byproduct |
1.6 ppb | 0.1 | — | — | — | — | — | 16× over |
| Dichloroacetic acid Disinfection byproduct |
3.06 ppb | 0.2 | — | — | — | — | — | 15× over |
| Bromoform Disinfection byproduct |
4.69 ppb | 0.5 | — | — | — | — | — | 9.4× over |
| Nitrate* Inorganic |
0.281 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.0× over |
| Nitrate and nitrite* Inorganic |
0.287 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.0× over |
| Radium, combined (-226 and -228)* Radiological |
0.07 pCi/L | 0.05 | 5.0 | — | — | — | — | 1.4× over |
| Chromium (hexavalent) Heavy metal |
0.0209 ppb | 0.02 | — | — | — | — | — | 1.0× over |
| Uranium Radiological |
0.31 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | Below guideline |
| Chlorate Disinfection byproduct |
148.4 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Chloromethane Other |
0.978 ppb | 2.69 | — | — | — | — | — | Below guideline |
| Aluminum* Heavy metal |
77.5 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Molybdenum Other |
3.35 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.767 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
2.9 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Barium Heavy metal |
18.5 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Strontium Radiological |
0.539 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Bromomethane Other |
0.135 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.477 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Lithium Other |
10.3 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 GSWC - SOUTHWEST.