By Da Lin

CONCORD (CBS SF) — Pools and water parks across the San Francisco Bay Area were in high demand Saturday due to the scorching heat.

Six Flags Hurricane Harbor in Concord filled up as soon as they opened their doors on Saturday morning.

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“It’s extremely hot, but it’s really beautiful,” said Napa resident Jessica Olivera. “We’re enjoying the day with the kids.”

Workers at the water park said it could be a single-day record crowd for this year. They said roughly 6,000 to 7,000 people enjoyed the slides, the wave pool and the lazy river.

“I’m gonna get back in that water,” said Christopher Haynes, who came from Sacramento. “I feel dehydrated right now. So I’m just trying to stay cool and keep these two (kids) cool.”

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“I just love spending time with my grandparents and my brother right here. We both love to swim, and I just love spending time with them,” said Dayhan Polar of Oakland.

Most outdoor places were very quiet. People avoided outdoor dining to eat inside with the air conditioning running.

“We have a full house inside, but nobody wants to sit outside,” said John Marquez, chef and owner of Lima Peruvian Restaurant. “People are going to have to wait if they want to eat (inside.) There’s very good AC inside. We have two AC’s, double AC inside.”

Cal ISO asked people to set their thermostats to 78 degrees or higher to help conserve energy during the Saturday 4 p.m. to 9 p.m. Flex Alert. The governor also signed an executive order to free up additional energy to avoid rolling blackouts.

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“At the peak time, we’re using about 30,000 megawatts. And on a really hot Summer day, we’re using 40,000 to 45,000 megawatts — that difference is almost all air conditioning,” said Dr. Severin Borenstein, a UC Berkeley energy professor and a member of the Board of Governors for Cal ISO.