A POLITICIAN and taxpayer alike, the prospect of devoting more money and space to building yet another storage facility for criminals is never all that attractive. But neither are the pressures of prison overcrowding, as the lawmakers and top executives in Maryland, Virginia and the District are constantly reminded by escapes and disturbances. While the governors and state legislators in Richmond and Annapolis wrestle with various proposals for prison improvements, Mayor Marion Barry and the D.C. Council also have decided to take a fresh look at the issue -- with fresh prospects for financial assistance.

Until recently, Mr. Barry wanted no part of any proposal for significant expansion of either the D.C. Jail near RFK Stadium or Lorton Reformatory, the city's prison in Fairfax County. But with an offer of possible federal land and money for a new facility, the mayor is understandably willing to reconsider. That's good, because right now the system is bursting at the seams. At last count, the jail and prison were exceeding their total capacity by about 1,250 inmates. No matter how creative the city might become in finding alternative facilities for the less violent, something new needs to be built.

Potential sites, including Bolling Air Force Base and another property along the Anacostia River, are owned or controlled by the federal government, according to City Administrator Thomas Downs. As a result of the offer, the city government is considering a study of the feasibility of building a prison in the District. Given the new possibilities for an in-city facility, a study may be in order. But studies have a way of wander- ing onto shelves; with prompt approval of the necessary budget provision, this one could and should get under way quickly and lead to some action.

In the meantime, the city's department of corrections is working on a profile of the D.C. prison population to find out if there are any inmates who might be released safely and/or put into other programs. That, too, should be completed as quickly as possible, because the findings are critical to any sensible debate about the size and shape of the District's corrections system.