A look at competing math on pools versus lawns

A look at competing math on pools versus lawns
In this photo taken on Thursday, May 21, 2015, Jake Hall, 10, dives into a backyard pool in Long Beach, Calif. As residents struggle to reduce potable water consumption by 25 percent, the California Pool and Spa Association is promoting a campaign called Let's Pool Together and aggressively lobbying water districts to quash proposed bans on filling pools and spas. (AP Photo/Chris Carlson)

The drought gripping California has the swimming pool and spa industry on the offensive. Pool contractors worry about damage to their business as water districts consider bans on filling new pools and refilling existing ones.

Here is a look at the numbers being cited by three different parties who are concerned about the installation—or lack of installation—of new pools in California this summer:


The California Pool and Spa Association estimates that, after an initial fill, a standard-sized backyard swimming pool plus deck results in one-third less use than a similarly sized, irrigated lawn. The calculation is for a pool with no evaporation cover.

With a cover, the pool becomes as efficient as a backyard planted with drought-tolerant, California-native plant species, according to John Norwood, the association's president and chief lobbyist. Norwood's calculations assume the pool and deck together cover 1,200 square feet.

"You're talking 7 to 200 gallons a day from a leaking toilet and how many toilets are there in California? Do the math. It's crazy," Norwood said. "A symbolic gesture is not worth putting people out of business."


Some water districts considered bans on filling and refilling pools, but rolled them back after hearing from the industry. Even so, water districts' estimates of water use by a pool differ from the industry's.

The Santa Margarita Water District in Orange County last year abandoned plans for a ban on new swimming pools, but did its own calculations and now provides a widget on its home page that helps prospective pool permit applicants design an efficient pool.

The district estimates that a pool and deck covering 1,000 square feet uses about 3,000 gallons less than traditional lawn the first year but breaks even within three years. With a pool cover on 70 percent of the time, the district says, a pool will use more than five times less water than a traditional landscape and still less than a drought-tolerant landscape of native California plants.

"We're comfortable with three-year break-even point, but the message is that a pool can be more efficient than even California-friendly turf if it's covered," said Jonathan Volske, spokesman for the water district.


Californians have no business putting in new pools or refilling drained in a drought, according to Peter Gleick, president of the Pacific Institute, a nonprofit research institute in Oakland that focuses on the environment and sustainability issues.

Variables such as splash rate, whether a pool is covered and how the lawn was managed before it was ripped out make the pool-versus-lawn calculation almost meaningless—although they probably roughly use the same amount of water, he said.

But such calculations miss the point: Instead of installing a pool, homeowners should be letting their lawns die or replanting with drought-tolerant species to save water, he said.

"It's all about the choices you make," Gleick said. "We're in a drought and if you have a pool, I'm not saying remove it—but you sure better cover it."

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