Water Quality Report · Updated May 12, 2026
CITY OF REDWOOD CITY
CITY OF REDWOOD CITY delivers tap water graded C (67/100) by TapWaterSafety.org. The utility serves approximately 92,819 residents in REDWOOD CITY, California using surface water (purchased). The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline. For questions, the utility can be reached at 650-780-7466.
Is REDWOOD CITY tap water safe to drink?
CITY OF REDWOOD CITY delivers tap water that earns a grade of C (67/100) from TapWaterSafety.org — an average rating, with several contaminants above health guidelines but generally compliant with US legal limits.
The utility serves 92,819 residents in REDWOOD CITY, drawing from surface water (purchased).
Public testing data identifies 8 contaminants in this water above EWG's health-based guidelines, including: Haloacetic acids (HAA9), Haloacetic acids (HAA5), Total trihalomethanes (TTHMs), Trichloroacetic acid, Dichloroacetic acid, Chloroform, Bromodichloromethane, Chromium (hexavalent). 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 REDWOOD CITY residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for CITY OF REDWOOD CITY.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 33.4 ppb, 557x above the EWG health guideline of 0.06 ppb.
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.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 38.1 ppb, 254x above the EWG health guideline of 0.15 ppb.
Contact CITY OF REDWOOD CITY
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Recommended water filters for REDWOOD CITY
Filters matched to the specific contaminants in this water supply.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
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 67/100 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 |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
33.4 ppb | 0.06 | — | — | — | — | — | 557× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
36.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 362× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
38.1 ppb | 0.15 | 80.0 | 100 | — | — | — | 254× over |
| Trichloroacetic acid Disinfection byproduct |
13.6 ppb | 0.1 | — | — | — | — | — | 136× over |
| Dichloroacetic acid Disinfection byproduct |
18.9 ppb | 0.2 | — | — | — | — | — | 94× over |
| Chloroform Disinfection byproduct |
36.7 ppb | 0.4 | — | — | — | — | — | 92× over |
| Bromodichloromethane Disinfection byproduct |
1.38 ppb | 0.06 | — | — | — | — | — | 23× over |
| Chromium (hexavalent) Heavy metal |
0.03 ppb | 0.02 | — | — | — | — | — | 1.5× over |
| Chlorate Disinfection byproduct |
131.0 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Dibromochloromethane Disinfection byproduct |
0.0114 ppb | 0.1 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
1.75 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.49 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.125 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.028 ppb | 1500.0 | — | — | — | — | — | 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.
CITY OF REDWOOD CITY service area
This water system serves 1 community in San Mateo County, California. Click any city for its dedicated tap water quality page.
Find the right filter for REDWOOD CITY water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.