The largest pool in the U.S. was once in San Francisco

The facade of the Fleishhacker Pool poolhouse, a city landmark from 1924 to 2012, can be found in the parking lot of the San Francisco Zoo. The facade of the Fleishhacker Pool poolhouse, a city landmark from 1924 to 2012, can be found in the parking lot of the San Francisco Zoo. Photo: Blair Heagerty / SFGate Photo: Blair Heagerty / SFGate Image 1 of / 25 Caption Close The largest pool in the U.S. was once in San Francisco 1 / 25 Back to Gallery

If you pull into the parking lot of the San Francisco Zoo you might notice an ornate building facade that stands behind a barbed wire fence, seemingly out of place and without any historical explanation.

That crumbling face and its decorative carvings were formerly part of the Fleishhacker Pool poolhouse, a city landmark from 1924 to 2012. The gigantic pool it served was built by Bay Area local philanthropist and city Parks Commissioner Herbert Fleishhacker to accommodate 10,000 swimmers.

The pool opened on April 23, 1925. It was filled by 6.5 million gallons of saltwater pumped in from the nearby ocean at high tide. At 1,000 feet long and 150 feet wide, plus a separate tiered diving tower, it was the largest pool in the United States at the time. Local lifeguards used wooden rowboats to traverse the expanse it was so large.

It opened to much fanfare from the city and it was said that in the 1920s and 1930s movie stars such as Johnny Weismuller, Esther Williams and Ann Curtis all swam there.

The water was heated, though it generally fluctuated between 65 and 75 degrees — a chilly temperature for most swimmers.

The pool was even used for aquatic drills by the military during war years.

We asked the Facebook group San Francisco Remembered for their memories swimming in the pool. Sandy Shaw said she learned how to swim there and it was also where she got her first summer job when she was 14 (in 1960) as a “Locker Girl,” “My duties entailed checking stamp on hand to make sure they paid the entry fee, monitoring & overseeing the public/swimmers re policies, rules and guidelines for safety (i.e., running, wearing the proper foot protection, etc.) handing out & gathering the towels, sweeping and hosing down the entire locker room, including the shower area (it was huge!)”

Many people remembered passing swim tests at the pool for San Francisco public schools (which required learning to swim for graduation) as well as competing in swim competitions in the pool. Mike Murphy said, “All City Swim Meets were held there. I was on the Mission High swim team. I spent a lot of time there.”

Elizabeth Damon Mitchell said, “Yes! I remember finally being allowed to swim in the deep end when I passed the swim 'test.' I think I had to swim a lap across and tread water for one minute. Salty and freezing! Then I got to swim a long lap from end to end. Good times.”

Ellie Cannon added, “Red Cross swimming lessons were five cents. It was cold there for sure.”

A few mentioned that there was even a longstanding rumor that a shark roamed the pool.

Unfortunately, strong storms in 1971 caused extensive damage that eventually led to the pool’s closure. Studies showed that public usage was extremely low (22,140 in 1970), the annual operating costs were high ($56,000), and there was little revenue ($6,000) to offset these costs, according to the San Francisco Zoo.

Refurbishment was out of the question.

The abandoned poolhouse was left neglected for years, only to be extensively graffitied and left to play host to raccoons, feral cats and the occasional squatter.

On December 1, 2012 a fire broke out, leaving only the facade you can see now.

Today, the filled-in pool operates as a guest parking lot run by the San Francisco Zoological Society with oversight by San Francisco Recreation and Park Department. The city still owns the land.

Did you swim in the Fleishhacker pool while growing up in San Francisco? Share your memories in the comments! Have photos to share? Send them to tessa.mclean@sfgate.com

Tessa McLean is a digital editor with SFGATE. Email her at tessa.mclean@sfgate.com or follow her on Twitter @mcleantessa.