The Fleishhacker mega pool

Pools come in all shapes and sizes, but none so big as The Fleishhacker Pool which was once the largest swimming pool in the United States.

Opened on 23 April 1925, it measured 300m by 45m (1,000ft by 150ft) and was so large that the lifeguards required kayaks for patrol! It closed in 1971 due to low patronage.

Fleishhacker Pool or Delia Fleishhacker Memorial Building was a public saltwater swimming pool located in the southwest corner of San Francisco, California, United States, next to the San Francisco Zoo. Upon its completion in 1925, it was one of the largest heated outdoor swimming pools in the world, and remained open for more than four decades until its closure in 1971. It was eventually demolished in 2000.

It was built by philanthropist and civic leader Herbert Fleishhacker in 1924 and opened April 22, 1925. The pool held 25,000,000 litres of seawater, and accommodated 10,000 bathers. The pool was often used by the military for drills and exercises.

Water for the pool was pumped from the Pacific Ocean, filtered and heated. The pool's heater could warm 11,000 litres of seawater from 60 degrees to 75 degrees Fahrenheit each minute. This resulted in a constant pool water temperature of 72 degrees for Amateur Athletics Association swim meets.

The water was provided by a series of pumps and piping at high tide, directly from the Pacific Ocean 200 metres away.

After years of underfunding and poor maintenance, the pool was showing some deterioration when a storm in January 1971 damaged its drainage pipe. Because the repair costs exceeded the City's budget, the pool was converted to fresh water which resulted in poor water quality. Because of the poor attempt at conversion and resulting water quality, the pool was closed by the end of 1971.

In 1999, the San Francisco Zoological Society was granted ownership of the pool house. The swimming pool itself was filled with rocks and gravel, with the space now serving as a parking lot for the zoo.

The pool house was derelict, neglected, and occupied by the homeless for many years until it was destroyed by a fire on December 1, 2012. The remaining ruins were demolished, and only a fragment consisting of three ornate entrances remains to mark the site.

It's a shame such an amazing structure was allowed to fall into disrepair! If you accidentally let your pool turn into a swamp this winter we've got you covered! Read our tips on green pool maintenance at the link below.