WASHINGTON — It’s been on the wish-list for Arlington and Alexandria residents for years — a new aquatics center with a 50-meter pool.  But it’s such a pricey proposition that they’ve had to go without.

Now a new idea is being floated that might make it affordable: What about a joint aquatics and fitness center that Arlington and Alexandria could share?

Craig Fifer, Alexandria’s director of communications and public information, says that at this point it’s only an idea. But two locations are being discussed: One is at Alexandria’s Chinquapin Park on King Street, right next to T.C. William High School; the other, in Arlington, at Long Bridge Park in the Crystal City/Pentagon area.

“It’s just the concept that we’re discussing to see if it would work out well for everybody,” Fifer says.

He says they will survey residents to first see whether there is enough interest. If there is, the next step would be to begin looking at designs and costs.

Fifer says, “The city included a question on its annual park survey, which is underway right now, to gauge our community’s interest,” and adds that Arlington will ask its residents during a survey in the fall.