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The Perfect Pool Blog

Zodiac's In-Depth Resource for All Things Pool.

9 Cool Facts About Swimming Pools



Pool Resolutions

Swimming pools are popular for many reasons. But did you know when the first pool was invented or just how popular they are in this country? Here are some fun facts about swimming pools.

1. The first pool was built more than 5,000 years ago. Known as the Great Bath of Mohenjo-daro, this pool, discovered in Pakistan, was a fairly complex structure. The in-ground pool was constructed entirely out of brick, plastered with gypsum, and even waterproofed with a tar membrane. It included stairs on two sides for swimmers to enter and exit, benches, and a pool deck. Anthropologists speculate that the pool was mostly used for religious rituals rather than for recreation.

2. Modern-day swimming pools became popular in Britain in the mid-1800s. By 1837 there were six indoor pools in London, complete with diving boards. The Maidstone Swimming Club in Maidstone, Kent, was possibly the first swim club, created in 1844. Its founding was meant to teach people to swim to combat the number of drownings in the River Medway, including rescuers who couldn’t swim. The club held races, diving competitions and water polo matches in the river.

3. The RMS Olympic, known as a sister ship to the Titanic, was the first oceanliner to have a heated swimming pool on board. The 30-foot pool was only available to first-class passengers. It set sail the year before the Titanic did. The Titanic had a similar heated pool on board.

4. A dedicated filtration system for swimming pools was invented in 1910 at Brown University, using chlorine. By then public drinking water was being sanitized with chlorination and sand filtration, and the same concept was applied to swimming pools.

5. The White House has two swimming pools: an indoor pool and an outdoor pool. The indoor pool was built in 1933 for Franklin D. Roosevelt. Its construction was made possible by a fundraising campaign led by the New York Daily News so the president, who suffered from polio could continue his water therapy during his terms. In 1970 President Nixon made a decision to close the pool to build a press briefing room above it to accommodate the growing presence of television cameras. But President Gerald Ford, who was an avid swimmer and had a pool at his home in Alexandria, made the construction of an outdoor pool one of his first orders as president in 1975. It rests on the White House lawn, and is accessible by a tunnel passage so the president and family can access it without being seen by the media, the public, or by spies.

6. As of 2015, the United States has an estimated 5.14 million residential inground pools, 3,394,565 aboveground pools, and 243,499 public pools nationwide, according to the Association of Pool and Spa Professionals. There are also 5,639,264 hot tubs in the United States.

7. California ranks at the top with the most swimming pools in the country, at 1,233,611 inground residential pools, 335,988 aboveground pools and 40,536 commercial pools. It also ranks at number one with 1,197,471 hot tubs. Florida ranks second in number of inground residential pools at 1,027,846, while Texas comes in third at 397,793.

8. A Olympic-sized swimming pool, which is 50 meters by 25 meters and at least 2 meters deep, has enough water to fill 9,400 bathtubs. That’s 660,000 gallons of water (if a bathtub holds 70 gallons).

9. The deepest indoor pool is Nemo 33, in Brussels. It’s 113 feet deep, but maintained at 86 degrees for comfort, so divers can swim without worry about hypothermia.

While enjoying these facts, please note these are fun facts used for entertainment value, Zodiac does not lay claim to the validity.

Sources: AQUA magazine, FINA, APSP, White House Archives, National Museums of Northern Ireland, Maidstone Swimming Club