(File photo)

It is expensive to build an indoor swimming facility anchored by a 50-meter pool. The City of Alexandria and Arlington County both found this out the hard way in recent years. The localities have seen estimates to build aquatic centers containing Olympic-sized pools skyrocket beyond their budgets during feasibility studies conducted by Hughes Group Architects.

Alexandrians were shocked in March when Hughes increased its estimate to build a 50-meter pool at the site of the current Chinquapin Park pool to almost $31 million, an increase of around 50 percent over a November 2014 projection. Arlington had previously received similar sticker shock from the same architectural firm when it explored building a 50-meter pool at Long Bridge Park.

With both localities facing budget-busting project costs coupled with increasing aquatic demand, it’s not surprising that a joint facility is under consideration. On face value, this seems like a promising solution.

Neither Alexandria nor Arlington currently has a public 50-meter pool, so adding such a facility to be shared between the two jurisdictions would be better than the status quo. But ultimately, the key issues are not only cost, but also location and access. And it’s far from certain that questions around all three issues can be adequately answered.

For starters, will Arlington or Alexandria really pony up millions of dollars to build a facility in the other jurisdiction? What process would be used to determine which locality gets the pool? If the pool is built at Long Bridge, will that meet the needs of Alexandria swimmers — many of whom will likely lack transportation to Arlington — and, similarly, will a pool at Chinquapin meet Arlingtonians’ needs?

The question of access also must be resolved. Alexandrians would need concrete assurances that a Long Bridge facility would be as open to them as it would be to Arlington residents. Conversely, if a shared pool were built here, Alexandrians would have to accept that at times Alexandria swimmers or groups may be turned away from a pool filled with Arlington residents. Is that acceptable?

And, of course, there’s the thorny budget issue. Although the facility would be used for all waterborne activities, it would most benefit competitive swimmers. That must be balanced with demand for upgrades to community pools throughout the city.

Spending money on aquatics also must be considered in the context of the larger budget. Unless tax rates rise exorbitantly, city spending really is a zero-sum exercise. A project like this, which most people would consider optional when compared to paying police officers, building schools and fixing potholes in streets, has to be placed into that broader context. And that’s before considering the financial impact of building a Metro station at Potomac Yard.

The idea of a shared 50-meter pool between Alexandria and Arlington is worth exploring. But let’s not rent the backhoe and plan the dig just yet.