BOSTON -- New federal regulations mean that about 20 indoor pools in the city of Boston will close their doors Friday for safety reasons.

NewsCenter 5's Steve Lacy reported that the pool at Curtis Hall in Jamaica Plain will be the only indoor pool run by the city that will be allowed to remain open to the public.

Tough new safety requirements regarding pool drain covers that go into effect Dec. 19 apply to any pool or spa that is publicly used, including municipal pools and those at hotels, private clubs, apartment buildings and community centers.

New rules require that all pools have drain covers in an attempt to prevent children from drowning when they get pulled under water by powerful pool drains. The law was inspired by the 2002 death of former Secretary of State James Baker's 7-year-old granddaughter.

According to the Consumer Product Safety Commission, 74 children were injured after becoming entrapped by drains in pools and spas between 1999 and 2007, with 63 were injured and nine killed.

Most Boston Center for Youth and Family pools are expected to reopen by the middle of January.

The National Swimming Pool Foundation, a nonprofit group in Colorado Springs, Colo., said about 80 percent of the 300,000 public pools and spas in the United States do not comply with the new rules and may have to close.

The foundation says the costs of complying with the new law would range from $1,000 to $15,000 per pool. A variety of factors, including the availability of compliant drains from manufacturers and the workers to install them, determine the eventual price tag.

Given current economic conditions, that's a potentially heavy financial burden for local governments.

"The challenge here is to solve one problem without creating another," said Tom Lachocki, the foundation's chief operating officer.

Lachocki said very few people die from drain-suction entrapment each year, while hundreds drown for other reasons. The number of drownings could go up if pools close and children can't take swimming lessons, Lachocki said.

Nord had no sense of how many pool and spa owners had installed the new equipment or how many might have to close.

"Our message to pool and spa owners is to make sure they check their pool and make sure they are in compliance," she said, adding: "We have limited resources and we don't have the resources to send federal safety inspectors to every single pool."

At the same time, she said, her agency reserves the right to take action against violators of the law.

The legislation bans the manufacture, sale or distribution of drain covers that don't meet anti-entrapment safety standards.

New models use a hump-shaped drain cover rather than the flat style that more easily attains suction with a child's body. Pools with just one drain also are required to install a second drain system, or external shut-off.

Alan Korn, public policy director of the Washington-based nonprofit group Safe Kids Worldwide, said the vast majority of American swimmers don't realize that the bottom of pools and spas and wading pools are a hidden hazard, especially to children.

He said one person dies because of pool or spa drain suction in a typical year. His agency cited 33 deaths of children under age 14 between 1985 and 2004.

The new drain-cover rule also applies to new portable hot tubs sold for backyard use by consumers. The rules to do not apply to existing hot tubs.

The Association of Pool & Spa Professionals says its existing drain covers are safe and wants Nord's agency to recognize that new equipment entails a flow level below what is needed to run a portable hot tub, said spokesman Dick Wolfe.

Wolfe said virtually all the 70 or so hot tub manufacturers in the country would go out of business if they had to build their spas to meet the news requirements. The group has asked CPSC for an exemption for hot tubs.

Scott Wolfson, spokesman for the CPSC, said the agency was reviewing the association's request.