Water Quality Report · Updated May 12, 2026
CALDWELL CITY OF
CALDWELL CITY OF delivers tap water graded C (66/100) by TapWaterSafety.org. The utility serves approximately 74,000 residents in CALDWELL, Idaho using groundwater. The most significant water quality concerns are: Arsenic significantly above health guideline; Chromium (hexavalent) significantly above health guideline. For questions, the utility can be reached at 208-455-4793.
Is CALDWELL tap water safe to drink?
CALDWELL CITY OF delivers tap water that earns a grade of C (66/100) from TapWaterSafety.org — an average rating, with several contaminants above health guidelines but generally compliant with US legal limits.
The utility serves 74,000 residents in CALDWELL, drawing from groundwater.
Public testing data identifies 5 contaminants in this water above EWG's health-based guidelines, including: Arsenic, Chromium (hexavalent), Uranium, Nitrate, Nitrate and nitrite. 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 CALDWELL residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for CALDWELL CITY OF.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 8.3 ppb, 2075x above the EWG health guideline of 0.004 ppb.
Chromium (hexavalent) significantly above health guideline
Moderate concernChromium (hexavalent) detected at 3.08 ppb, 154x above the EWG health guideline of 0.02 ppb.
Contact CALDWELL CITY OF
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 CALDWELL
Filters matched to the specific contaminants in this water supply.
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 66/100 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 |
8.3 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 2075× over |
| Chromium (hexavalent) Heavy metal |
3.08 ppb | 0.02 | — | — | — | — | — | 154× over |
| Uranium Radiological |
4.02 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 9.3× over |
| Nitrate Inorganic |
0.71 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 5.1× over |
| Nitrate and nitrite Inorganic |
0.3 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 2.1× over |
| Vanadium Other |
8.93 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
29.6 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
2.85 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
1.41 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.164 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.4 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Germanium Other |
0.228 ppb | — | — | — | — | — | — | Below guideline |
| Lithium Other |
7.36 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.
CALDWELL CITY OF service area
This water system serves 1 community in Canyon County, Idaho. Click any city for its dedicated tap water quality page.
Find the right filter for CALDWELL water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.