Tap water may turn milky on the Peninsula

San Francisco Public Utility Commission warns that water color may temporarily change because of increased air pressure

If Palo Alto residents notice their tap water turning white or milky in the coming month, it's not just their imagination at work.

The San Francisco Public Utilities Commission (SFPUC), which supplies water to San Francisco, Palo Alto and 26 other cities, is warning that tap water on the Peninsula and in the East Bay may turn cloudy between Dec. 5 and early January because of routine maintenance and seismic upgrades in the Central Valley. According to the SFPUC, the change in the water is "only aesthetic, with water continuing to meet all state and federal regulatory requirements."

During the time of the maintenance work, customers will not be receiving water from the Hetch Hetchy Reservoir -- the SFPUC's usual source -- but from local reservoirs.

According to the water agency, the increased treatment of the local-reservoir water at the SFPUC's Sunol Valley Water Treatment Plant will cause air to be mixed into the water, which makes water appear "cloudy or milky." The cloudiness dissipates if the water is allowed to stand for a few minutes, which causes the air bubbles to rise to the surface and dissipate.

Water officials expect water to return to normal when the work is completed in the week of Jan. 7.


Posted by smelly too?, a resident of Midtown
on Dec 2, 2011 at 6:35 pm

Is the water going to be smelly again?

Posted by Roger TC, a resident of University South
on Dec 2, 2011 at 10:11 pm


I think it must be causing the water to be both. I've been out sick all week and every time I ask my roommate for cold water he brings it, its both milky AND smelly. Salty too.

Posted by Walter_E_Wallis, a resident of Midtown
on Dec 3, 2011 at 4:32 am

Walter_E_Wallis is a registered user.

If it is gonna foam, it might as well be beer.

Posted by Marie, a resident of Midtown
on Dec 3, 2011 at 1:54 pm

This is very bad news.

Posted by Donald, a resident of South of Midtown
on Dec 3, 2011 at 4:17 pm

The article says the work will begin on Dec. 5, two days from now, so if you have problems now they are the result of something else.

Posted by PADenizen, a resident of Duveneck/St. Francis
on Dec 4, 2011 at 6:43 am

This happens every year at this time, and it happens in a lot of places. If I were the utilities company I'd try to do a better job of explaining why it happens. Here's some info from a Massachusetts utilities site:

This usually happens when it is very cold outside because the solubility of air in water increases as water pressure increases and/or water temperature decreases. Cold water holds more air than warm water. In the winter, water travels from the reservoir which is very cold and warms up during its travel to your tap. The air that is present is no longer soluble, and comes out of solution.

In addition, once water from our reservoir enters the transmission and distribution pipes, the water is pressurized. Water under pressure holds more air than water that is not pressurized.

Once the water comes out of your tap, the water is no longer under pressure and the air comes out of solution as bubbles (similar to a carbonated soft drink). The best thing to do is let it sit in an open container until the bubbles naturally disappear.

Posted by Blue Planet, a resident of Woodside
on Dec 5, 2011 at 10:32 am

Hetch Hetchy has been drawing water from it's lower reservoirs for about 1 1/2 months. The water is harder than the upper reservoirs but should not cause hardness scale. The water from these sources was very high in PH but ok. We have encountered green and blue water which is observable in bathtubs.
Smelly water is another matter. Best solution is to filter through carbon. A Brita Cartridge filter will do the trick for drinking water. If the objective is to remove the smell from all of the water coming into the home, then a whole house catalytic carbon filtration unit is needed (It also remove chloromines, trihalomethanes, free ammonia and free chlorine).

Posted by Tish, a resident of Greendell/Walnut Grove
on Dec 5, 2011 at 10:38 am

I have trouble drinking water to begin with, ugh.. It always smells and tastes funny to me..

Posted by Christian, a resident of Palo Alto High School
on Dec 5, 2011 at 1:30 pm

Jesus turned water into wine, the first miracle.

Palo Alto turns water into milk, the latest miracle!

Posted by william, a resident of Midtown
on Dec 26, 2011 at 2:40 pm

From the City's own web site: "Due to routine maintenance of the Foothill Tunnel and valve upgrades to the San Joaquin Pipelines, the Hetch Hetchy Aqueduct was completely shut down on December 5, 2011 and will stay closed until January 10, 2012."

So our water is coming from local sources, not Hetch-Hetchy until at least january 10. We've noticed that the water is cloudy due to small bubbles but that it clears within a minute or two, BUT - our fish tank is NOT happy! It's a well established tank, over 2 years with no problems, and now we have algae bloom. I don't have the right testing equipment but I suspect higher than normal phosphate levels due to the water source change and perhaps additives intended to prevent pipe corrosion. I'm going to have to switch to bottled water.

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