Los Altos Hills Tap Water Quality Report
Los Altos Hills's water has 3 contaminants above EPA MCLGs. Consider using a certified water filter for additional protection.
Other systems listed for Los Altos Hills with results above guidelines: SANTA CLARA VALLEY WATER DISTRICT (2 above guidelines)
Water system
CWSC LOS ALTOS SUBURBAN
2 other systems are listed for Los Altos Hills. See their figures
People Served
70,175
Health-based violations since 2020
0
CWSC LOS ALTOS SUBURBAN. EPA SDWA violation data as of Q2 2026 (downloaded 2026-07-09).
Latest sample on file
Sep 2025 · CWSC LOS ALTOS SUBURBAN
Utilities publish newer results in their annual water quality report (Consumer Confidence Report).
Is Los Altos Hills Tap Water Safe to Drink?
We recommend using a certified water filter for additional protection, especially for vulnerable populations like children, pregnant women, and those with compromised immune systems. Los Altos Hills's water has 3 contaminants above EPA health-based guidelines (MCLGs), while it meets federal legal limits.
CWSC LOS ALTOS SUBURBAN, Los Altos Hills's water system, serves 70,175 people. 2 other systems are listed for Los Altos Hills. Each system's results are listed under its own name, never added to CWSC LOS ALTOS SUBURBAN's. Water quality testing is conducted regularly and reported to the EPA. The latest sample on file for CWSC LOS ALTOS SUBURBAN is from Sep 2025.
Boil water advisories are issued by water systems and state agencies, and they change from day to day. Boil water advisories in California
Los Altos Hills Water Service Areas
What these numbers actually mean for Los Altos Hills, CA
We read Los Altos Hills, CA’s published record and send you a short report — which findings warrant a decision, which to ignore, and what to do about it. Including when the answer is nothing.
- 3 contaminants above EPA MCLGs, 10 contaminants with an EPA health goal detected in some samples (no level on file) and 1 nitrate reading above 10 mg/L whose basis is unconfirmed (above EPA's limit if measured as nitrogen, within it if measured as nitrate)
- 189 results on file
- 23 PFAS compounds on record
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Recommended Water Filters for Los Altos Hills
Based on Los Altos Hills's water quality data, these NSF-certified filters are recommended to remove contaminants above EPA MCLGs.
Culligan
ZeroWater
NSF Certified:
Flow Rate
1.9 gpm
Daily Production
1 gpd
Highlights:
- Compact design
- Easy to set up
- Affordable
- NSF-42, NSF-53, NSF-401 certified
Removes 19 contaminants:
+14 more
Strontium, Molybdenum, Fluoride, Uranium, Lead, Total PFAS, Chlorine, 25, Phosphorus, Bicarbonate, Calcium, Carbonate, Magnesium, Sodium
AquaTru
Classic
NSF Certified:
Flow Rate
0.04 gpm
Daily Production
600 gpd
Highlights:
- Best overall contaminant reduction score
- Most performance certifications
- Lifetime warranty
- NSF-42, NSF-53, NSF-58, NSF-401 certified
Removes 23 contaminants:
+18 more
Molybdenum, Barium, Chlorine, Arsenic, 83+ contaminants, Calcium, Chloride, Copper, Magnesium, Nitrate, Phosphorus, Sodium, Sulfate, Total Dissolved Solids, Zinc, Total THMs, Chloroform, Nitrate (as N)
AquaTru
Carafe
NSF Certified:
Flow Rate
0.3 gpm
Daily Production
4 gpd
Highlights:
- Verified PFAS reduction
- Glass collection vessel
- Plug-and-play installation
- NSF-53, NSF-42, NSF-58, NSF-401, NSF-372 certified
Removes 17 contaminants:
+12 more
Arsenic, 83+ contaminants, Copper, Total THMs, Chloroform, Chloride, Sulfate, Nitrate (as N), Molybdenum, Barium, Strontium, Uranium
Waterdrop
A1
NSF Certified:
Flow Rate
0.042 gpm
Daily Production
130 gpd
Highlights:
- Built-in UV sterilization
- Easy maintenance with filter change reminders
- NSF-58 certified
- Hot and cold water dispensing
Removes 12 contaminants:
+7 more
Molybdenum, Sulfate, Strontium, Phosphorus, Chlorine, Barium, Nitrate
Verify Your Water Quality with Independent Testing
With 3 contaminants above EPA MCLGs, 10 contaminants with an EPA health goal detected in some samples (no level on file) and 1 nitrate reading above 10 mg/L whose basis is unconfirmed (above EPA's limit if measured as nitrogen, within it if measured as nitrate), independent laboratory testing provides a second opinion and can track changes over time.
SimpleLab
Advanced Home Water Test
$269
Comprehensive water analysis testing over 200 contaminants including bacteria, heavy metals, and chemical compounds.
Tap Score
Advanced Microplastics Test
$829
Cutting-edge testing for microplastics particles in drinking water using advanced laboratory techniques.
Tap Score
Haloacetic Acids (HAA9) Test
$275
Tests for disinfection byproducts formed when chlorine reacts with organic matter in water treatment.
With 3 contaminants above health guidelines, you may want to explore water purification options. Learn how to make distilled water at home for applications like humidifiers, CPAP machines, and baby formula.
What Los Altos Hills's water readings can explain
Utility-reported data for Los Altos Hills includes turbidity, sulfate and a chlorine-based disinfectant — the readings behind these common tap water questions. We publish a city-level hardness figure for Los Altos Hills, resolved from its water systems where they report one and estimated from county sampling where they do not. Each page starts with the hot-tap and cold-tap check, then shows what your own water system reported.
On a private well near Los Altos Hills? Public-water results do not apply to private wells. See Santa Clara County well water testing and USGS risk data — modeled arsenic, nitrate, and the tests to run.
Water softener cost and installation in Los Altos Hills
Los Altos Hills's tap water measures 17.4 grains per gallon (298.0 mg/L) — very hard on the USGS scale, the range where scale on fixtures and appliances is the usual complaint.
Water softener cost for 17.4 gpg water in Los Altos Hills — equipment and local installation labour for your ZIP code, with the sizing arithmetic shown in full. For the national picture first, read what a water softener costs — equipment, installation labour and ten-year ownership, each separated out. For California as a whole, read water softener cost in California — priced against the plumber wage published for the state.
Frequently Asked Questions About Los Altos Hills Tap Water
Los Altos Hills's water has 3 contaminants above EPA MCLGs. While the water meets federal legal limits, we recommend using a certified water filter for additional protection, especially for vulnerable populations like children, pregnant women, and those with compromised immune systems.
Spotted something off on this page?
Residents keep our data honest.
This form corrects our data; it does not reach CWSC LOS ALTOS SUBURBAN. For a problem with your water now (discolored water, no water, low pressure, a leak), contact CWSC LOS ALTOS SUBURBAN directly.
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