Water Quality

Is my water safe to drink?
Yes. Water distributed by the City of Mountain View to its residents meets all U.S. Environmental Protection Agency (U.S. EPA) and California Department of Public Health (CDPH) standards.
Why does my water look cloudy?
Tiny air bubbles can cause cloudy water. The City often pumps water and this can introduce air into the system and create bubbles. The cloudy appearance will dissipate if allowed to stand for a few minutes.
Why is my water yellow or brown?
The most common reason for discolored water is household plumbing.  When water is not circulated regularly (such as in a guest bathroom), it can pick up color from galvanized or copper pipes. A rusting water heater can also discolor water. 

Water pipes can also accumulate small amounts of sediment over time.  When the sediment is stirred up by water flowing through the pipe, you may experience cloudiness or discoloration of your water.  The City routinely flushes its water system to remove sediment and this maintenance work can cause temporary discoloration of the water. In most cases, letting the water run five to ten minutes should clear the discoloration.  If the water does not clear, call Public Services at (650) 903-6329.
Does my drinking water contain fluoride?
Water delivered to Mountain View from the SFPUC is fluoridated, and Mountain View fluoridates the water which is delivered from the SCVWD and pumped from local groundwater wells. The concentration of fluoride in Mountain View’s water meets all water quality regulations and is within the range prescribed by the California Department of Public Health for preventing tooth decay.
What is water hardness?
Water hardness is a measure of dissolved minerals (usually calcium and magnesium) in water. Hardness results mostly from water coming into contact with soil and rock formations. Hard water is not a health hazard.
Do I need a water softener?

Mountain View’s water is characterized as soft to moderately hard, generally making water softeners unnecessary. Hardness is measured in milligrams of calcium carbonate (CaCO3) per liter. 17.1 mg/L of CaCO3 is equal to one grain per gallon of hardness. View the tables and map below for more information.

Water Hardness Scale

mg/L Grains Classification
less than 17.1 less than 1.0 Soft
17.1 - 60 1.0 - 3.5 Slightly Hard
60 - 120 3.5 - 7.0 Moderately Hard
120 - 180 7.0 - 10.5 Hard
over 180 over 10.5 Very Hard

2012 Sampling Results

Mountain View Water Sources mg/L Grains
SFPUC (Zones 1 & 2) 8-114 0.5 - 6.7
SCVWD (Zone 3) 82-118 4.8 - 6.9

Pressure Zone & Water Source Map

What should I do if I can't find the answer to my question here?
If you cannot find answers to your questions here, visit Ask Mountain View to submit an inquiry or request.