The Pacific Palisades reservoir was offline and empty when the storm hit earlier this week.

The Pacific Palisades Reservoir, which is part of the Los Angeles water supply system, was out of service when the devastating wildfire destroyed thousands of homes and other nearby structures.

Officials told The Times that the Santa Ynez Reservoir was shut down to repair its cover, leaving the 117 million gallon reservoir empty in the heart of the Palisades.

This comes amid growing questions about why firefighters ran out of water while fighting the blaze. Many fire hydrants along Palisades’ high streets ran dry, leaving firefighters struggling to fight the flames.

Officials of the Ministry of Water and Power said that the demand for water during the unprecedented fire made it impossible to maintain pressure on hydrants in high places.

Had the reservoir been operating, it would have increased water pressure in the Palisades Tuesday night, said former DWP General Manager Martin Adams, an expert on the city’s water system. But only for a while.

“Even now I would have ended up with a lot less pressure,” Adams said in the interview. “It could be Santa Ynez [Reservoir] did they help? Yes, to a certain extent. Would it have saved the day? I do not think so.”

A DWP official acknowledged that the absence of a dam may have contributed to reduced pressure and dry water mains in the upper reaches of the Palisades.

However, a spokesperson for the agency said in a statement that the DWP is still considering the impact of the dam being taken offline, and staff are still investigating the cause.

“Our main objective is to provide water throughout the city,” said a DWP spokesperson, adding, “This system was not designed for the bushfire situation we are dealing with.”

It is not clear when the reservoir went offline. Adams said that it had been out of service for a while due to the rupture of the cover and that the DWP’s water storage and supply infrastructure was still providing residents with water without interruption, until this week.

The water pressure in the upper Palisades is supported by three storage tanks, which hold 1 million gallons each. These tanks, which are part of a network of more than 100 throughout the city, are located at successively higher elevations in the coastal, hilly area, and water is pumped from the top of the tanks, then down by gravity to maintain pressure.

By 3 am on Wednesday, all three tanks had been searched.

The chief executive officer of the DWP, Janisse Quiñones, said that the tanks cannot be refilled quickly and the need for high places makes it difficult to pump water from the tanks in high places. In one incident, DWP workers trying to move water to fill a tank had to be evacuated, officials said.

Quiñones said that four times the normal water demand in the trunk line in a 15-hour period led to a drop in water pressure.

If the Santa Ynez Reservoir had been used at that time, Adams estimated, that demand would have been three times higher. The water in the lake would feed the firefighting equipment and assist the pumping stations in the storage tanks. But the lake “wasn’t going to last forever and it wasn’t going to be the solution,” Adams said.

“In the end, you would have arrived at the same place,” he added. Adams cautioned that he was basing his assertion on a rough estimate, and that he did not calculate a specific effect.

It is not yet clear whether this lake would have had a meaningful effect in fighting such a fierce fire. Researchers say urban water systems like the DWP’s aren’t designed to deal with wildfires that sweep across the landscape.

The National Weather Service had warned of “life-threatening” winds before the fire broke out. At the time, Adams said, the DWP’s options were limited. He noted that fire danger is not limited to the Palisades but exists throughout LA County.

If the DWP had held the water in the lake with a torn cover, the water would not legally be potable except in emergency situations.

And if the utility chose to start filling the lake over the weekend, before the high winds, Adams said it’s unclear if the water would have been added quickly enough to be useful.

“They were going to bet that there will be a devastating fire everywhere, something that no one has ever seen,” he said. “It would be an unusual bet.”

The reservoir is one of several used by the DWP across the city, with a capacity of more than 4.1 billion cubic meters of water. Including drainage dams, the city can store more than 91 billion liters across its major infrastructure. The Santa Ynez complex, with a capacity of 117 million gallons, is located between several water sources in the area, including a large pipeline from Stone Canyon and a smaller site, the nearby Palisades Reservoir.

The state is designing a system with renewables and multiple water sources. In a statement, the organization said that none of its infrastructure equipment failed on Tuesday and early Wednesday, but the “intensity” of the fire disturbed the existing conditions.

Joseph Ramallo, DWP communications officer, said the lake is expected to reopen in February. Its repair, he said, was necessary to comply with the laws governing water quality.

Adams said that if the Santa Ynez Reservoir was in normal use with a fully repaired cover, the water level would be well below maximum capacity.

During the winter, water levels are intentionally kept low due to the seasonal decline in water use by residents. If the water remains stagnant in the pool, there is a risk that the disinfectant, chloramine, will break down and the chlorine will evaporate, leaving behind ammonia that can promote the growth of bacteria in the water.

“You couldn’t have a whole bunch of water just sitting there,” Adams said. “That’s the water conservation battle – you have to keep your tanks and reservoirs moving.”

Angry residents have cited a lack of water pressure as one contributing factor in the destruction of 5,300 homes and buildings in LA, Santa Monica and Malibu. Community leaders like LA City Councilmember Traci Park and developer Rick Caruso have pointed to the issue as a sign of poor infrastructure maintenance.