Why are Bay Area hydrants spraying water on streets?

California is still under a statewide order to save water, so you might wonder why you are seeing fire hydrants around the Bay Area blasting out water.

It looks wasteful, but flushing water through hydrants is actually considered a critical part of keeping your drinking water clean. High velocity water scours the underground pipe system, clearing out sediment and chemicals that might otherwise flow out of your tap.

During the drought, many Bay Area communities put off flushing hydrants to save water, but now some are catching up on this kind of routine maintenance.

Crews in Calistoga in Napa County are flushing hydrants all over town for the first time in four years. Each time they open up a hydrant, 1,000 gallons of water per minute shoot onto the street and into storm drains. The team works as fast as possible, but has to let the water keep flowing until it runs clear - a process that was averaging about nine minutes per hydrant.

Derek Rayner with Calistoga Public Works says officials decided to flush the pipes after the nearby Kimball reservoir filled up. The reservoir supplies about 40 percent of Calistoga's water.

It will take the Calistoga crew several months to finish the town's 170 hydrants. They check water pressure and make sure each hydrant is working properly so it will be ready for an emergency. They also dechlorinate the water before it runs into the environment.

Many other Bay Area communities are also flushing hydrants now, but not all water agencies are ready to resume normal operations. Many California reservoirs still are not full and the Sierra snowpack remains below average.

A spokesman for the East Bay Municipal Utility District told ABC7 News officials are considering more pipe flushing in the future. But for now, they are primarily flushing only new and repaired pipes.

Tyrone Jue with the San Francisco Public Utilities Commission said the city is looking at flushing hydrants and pipes "strategically." Jue said sometimes regular customer water use is enough to keep pipes clear, but flushing might be needed in lower volume areas.

In the South Bay, the San Jose Water Company is one of the first to use a new truck-based flushing system that saves water. A special truck connects to hydrants and flushes the pipes by running water through a filter, so very little water ends up on the street. The system cost San Jose half a million dollars.

State water officials caution that even if you do see water gushing out of fire hydrants in the next few weeks, you should not assume the drought is over. The California Water Board is expected to decide next month whether to ease up on current restrictions.

Written and produced by Jennifer Olney.

Click here to learn more about flushing water mains.

Click here for a Facebook page promoting to stop hyrdrant water flushing.

Click here for full coverage on the California drought.

To learn how much water your city is required to cut back, click here. For water rebate information from Bay Area water suppliers, click here. You'll find tips about how to conserve water here and information on how to report water wasters #WhereYouLive, here.