Firefighters must rely on the water system to supply them with what they need to control wildfires.
It’s not that complicated: Water puts out fires.
That’s why there are fire extinguishers in every kitchen, and fire hydrants on every street.
But if a wildfire races through the Orinda hills on some hot, windy summer day, how much can a fire hydrant really do? And how much water will be available if a fire truck hooks up a hose to one?
In harsh fire conditions, such as the deadly Palisades fire of 2025, with multiple fire hydrants being tapped at once, the water pressure inevitably had to drop. Add residents running their sprinklers or hoses and the leaking water pipes of burnt down homes, and some fire hydrants completely dried out.
“A municipal water system like ours is meant to handle about 23 houses on fire,” said Christopher Tritto of the East Bay Municipal Utilities District (EBMUD). “But when you get an event like in Los Angeles where you’ve got blocks and blocks of homes on fire with all these hydrants being tapped at the same time, the pressure drops.”
In Orinda, the Moraga-Orinda Fire District (MOFD) works with EBMUD to supply water to all the fire hydrants in town, preparing the area for any potential fire.
The water goes into over 4,000 miles of pipe that extends out into the neighborhoods. Due to Orinda’s hilly terrain, some of the water needs to be pumped uphill to local water tanks. When the water is needed, gravity pulls the water back down through the pipes and to the homes, businesses, and of course, fire hydrants.
Making sure the water tanks are full is part of MOFD’s responsibility, and they must be monitored on a continual basis.
“Most days we have those (water tanks) filled because we want to make sure we’re cycling through the water at the correct pace so it doesn’t sit there too long and get stale,” Tritto said. “But if we know that there’s a higher fire risk because of a Red Flag Day [an alert for extreme fire conditions], we can pump extra water to really fill those up.”
And though usually pumping water uphill into tanks is done at night because of cheaper electricity costs, on Red Flag Days, EBMUD will take the more expensive route of filling the tanks in the middle of the day.
That was a lesson learned in the devastating Oakland Hills fire of 1991.
“The tanks weren’t full,” said MOFD Board President Craig Jorgens, an Orinda resident, “so they had less water than they wanted to have. So now we have an agreement with EBMUD that during Red Flag Days when the fire danger is greater, they fill [the tanks] all day rather than just at night.”
But sometimes fighting a fire requires more than full water tanks.
“If all the hydrants are feeding off of one main [water pipe],” said MOFD Fire Chief Jeff Isaacs, “and we have multiple resources connected to hydrants on that main, we could reach out to EBMUD and see if they could boost the pressure. Otherwise, we would have to remove engines from that main and have them go find water at another source.”
And finding and connecting to a secondary water source takes time that firefighters might not have in a major fire.
In addition, EBMUD and MOFD both have backup procedures in the case of a lack of water in the hydrants. EBMUD, for example, has overlaps within their piping system to make multiple water sources accessible to Orinda.
“If one supply from a reservoir is unavailable, we can usually tap into another supply,” said Tritto. “The pipes are often connected and have redundancies to make sure we can supply the hydrants.”
In a larger event like the Palisades fire, additional resources would be called in, such as Cal Fire (from the California Department of Forestry and Fire Protection) and other local fire departments. These other departments would bring in more fire trucks and personnel, and often offer aerial support, pouring in water from helicopters or planes.
“Unlike many communities, we have places that the helicopters can go dip water,” Jorgens said mentioning the Lafayette Reservoir and Briones Reservoir, next to the Orinda Country Club.
“We also have tanker trucks that we own and take out and stage appropriately. Depending on where the fire is, we know where to go to pre-position where the helicopters and fire trucks can get to. They can carry up to 1,500 gallons,” Jorgens said.
A mutual aid agreement between local fire districts and departments allows them to share resources. For major fires, multiple departments would likely be called in, making it a multi-agency response.
In the case of high-wind conditions preventing additional aerial support systems, Orinda would have to rely more heavily on additional engines and personnel bringing in the water from local reservoirs and for EBMUD to pump and direct their water to the area in danger.
But how much water is available and where does it come from?
EBMUD water comes from the Mokelumne River watershed in the Sierra Nevada. It’s stored in the Pardee Reservoir, which is then brought to the East Bay through 90 miles of aqueducts in the Central Valley, blending with local rain runoff from local reservoirs.
As of early April, there has been a decent amount of rain, said Tritto, but not very much snow, and due to the warm weather, the majority of it has already melted.
“Most of what we’ve collected has melted and we’ve collected as much as we can in our reservoirs already,” Tritto said. “That’s what we have on hand to get us through the year. It should be more than enough.”
But having the water and transporting it to where it’s needed most during a major fire are two different things – and Orinda’s fire hydrants will need support from many different sources to keep the water flowing during a major fire.
“What we do is make sure that we’re all as coordinated as we can be,” said Tritto, “to prepare for fire response and to help each other as needed with mutual aid.”
