Water Quality Report · Updated May 12, 2026
LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER
LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER delivers tap water graded F (53/100) by TapWaterSafety.org. The utility serves approximately 208,129 residents in ALHAMBRA, California using surface water (purchased). The most significant water quality concerns are: PFAS contamination; Arsenic significantly above health guideline; Perfluorohexane sulfonate (PFHXS) significantly above health guideline; Chromium (hexavalent) significantly above health guideline. For questions, the utility can be reached at 626-300-3300.
Is ALHAMBRA tap water safe to drink?
LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER delivers tap water that earns a grade of F (53/100) from TapWaterSafety.org — a poor rating, with significant contamination concerns and/or recent violations.
The utility serves 208,129 residents in ALHAMBRA, drawing from surface water (purchased).
Public testing data identifies 19 contaminants in this water above EWG's health-based guidelines, including: Arsenic, Perfluorohexane sulfonate (PFHXS), Chromium (hexavalent), Haloacetic acids (HAA5), Haloacetic acids (HAA9), Total trihalomethanes (TTHMs), Dibromoacetic acid, Dibromochloromethane, Bromodichloromethane, Bromate*, Bromoform, Trichloroacetic acid, Dichloroacetic acid, Nitrate, Chloroform, Perfluorooctanoic acid (PFOA), Nitrate and nitrite, Uranium, Radium, combined (-226 and -228)*. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
Quick actions for ALHAMBRA residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER.
PFAS contamination
Severe concernPerfluorooctanoic acid (PFOA) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 4.79 ppb, 1197x above the EWG health guideline of 0.004 ppb.
Perfluorohexane sulfonate (PFHXS) significantly above health guideline
Moderate concernPerfluorohexane sulfonate (PFHXS) detected at 1.06 ppt, 1059x above the EWG health guideline of 0.001 ppt.
Chromium (hexavalent) significantly above health guideline
Moderate concernChromium (hexavalent) detected at 8.02 ppb, 401x above the EWG health guideline of 0.02 ppb.
Contact LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for ALHAMBRA
Filters matched to the specific contaminants in this water supply.
Reverse Osmosis or NSF P473 certified carbon
$80-$750Activated carbon and RO are the only technologies proven to remove PFAS at certified levels.
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.
Score breakdown
This utility's overall score of 53/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). 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 |
|---|---|---|---|---|---|---|---|---|
| Arsenic Heavy metal |
4.79 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 1197× over |
| Perfluorohexane sulfonate (PFHXS) PFAS |
1.06 ppt | 0.001 | 10.0 | — | — | — | — | 1059× over |
| Chromium (hexavalent) Heavy metal |
8.02 ppb | 0.02 | — | — | — | — | — | 401× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
16.4 ppb | 0.06 | — | — | — | — | — | 274× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
25.9 ppb | 0.15 | 80.0 | 100 | — | — | — | 172× over |
| Dibromoacetic acid Disinfection byproduct |
3.52 ppb | 0.03 | — | — | — | — | — | 117× over |
| Dibromochloromethane Disinfection byproduct |
10.0 ppb | 0.1 | — | — | — | — | — | 100× over |
| Bromodichloromethane Disinfection byproduct |
5.6 ppb | 0.06 | — | — | — | — | — | 93× over |
| Bromate* Disinfection byproduct |
2.21 ppb | 0.1 | 10.0 | 10 | 10 | 0.1 | — | 22× over |
| Bromoform Disinfection byproduct |
7.38 ppb | 0.5 | — | — | — | — | — | 15× over |
| Trichloroacetic acid Disinfection byproduct |
1.25 ppb | 0.1 | — | — | — | — | — | 13× over |
| Dichloroacetic acid Disinfection byproduct |
2.16 ppb | 0.2 | — | — | — | — | — | 11× over |
| Nitrate Inorganic |
1.55 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 11× over |
| Chloroform Disinfection byproduct |
2.79 ppb | 0.4 | — | — | — | — | — | 7.0× over |
| Perfluorooctanoic acid (PFOA) PFAS |
0.613 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 6.8× over |
| Nitrate and nitrite Inorganic |
0.897 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 6.4× over |
| Uranium Radiological |
2.05 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 4.8× over |
| Radium, combined (-226 and -228)* Radiological |
0.18 pCi/L | 0.05 | 5.0 | — | — | — | — | 3.6× over |
| Vanadium Other |
15.5 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Perfluoropentane sulfonic acid (PFPeS) PFAS |
0.573 ppt | 1.0 | — | — | — | — | — | Below guideline |
| 6:2 Fluorotelomer Sulfonic Acid (6:2 FTSA) Other |
0.483 ppt | 1.0 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
46.2 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
3.99 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
35.7 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Bromochloromethane Other |
0.00108 ppb | 0.06 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.396 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.749 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
4.22 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
3.23 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Aluminum* Heavy metal |
1.46 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
1.24 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.0469 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
1.34 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Perfluoroheptanoic acid (PFHPA) PFAS |
0.404 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.352 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chromium (total) Heavy metal |
9.34 ppb | — | 100.0 | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.34 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Germanium Other |
0.00846 ppb | — | — | — | — | — | — | Below guideline |
| Lithium Other |
1.3 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 (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER service area
This water system serves 1 community in Los Angeles County, California. Click any city for its dedicated tap water quality page.
Find the right filter for ALHAMBRA water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.