MORE THAN 1,000 apartments with low to moderate rents in the Arlandria section of Alexandria -- the homes of thousands of poor Washington-area immigrants -- have been sold. Arlandria will be transformed into an area of high-priced residences and sparkling new developments.

Arlandria sits in the Four Mile Run flood plain, which kept rents low for years. But a flood control project has removed that threat. Property values have soared, and the tax benefits to Alexandria will be great. Few can argue against that. But it also means that the last large section of private, low-income housing near the District will be lost. Residents there, who work the lowest-paying, but still important, jobs in the area, will have to move much farther out of town.

The best the city of Alexandria says it could do was offer the developers tax-exempt financing, which would have required that a fraction of the new units have moderate rents. The developers did not want that financing. They are not legally bound to keep some low-priced units. The same developers took over the moderately priced Abingdon apartments in Alexandria. Rents increased as much as $300 a month, and all the tenants were displaced. What does it matter to the local jurisdictions?

It matters to straining businesses already short on clerical, maintenance and restaurant help, to secretaries and teachers, low-level professionals, police and firefighters who can't afford to live in the jurisdictions in which they work. It matters because local governments and developers and businesses can pool their resources and devise ways to ease the housing situation. It matters because neighbors can rein in a bit of the selfish disgust for lower-priced housing that frightens their elected officials.

For a generation, federal funds were used to provide the housing assistance. The fact that those funds have dried up does not relieve localities of the obligation to help. Some suggestions have ranged from offering developers higher-density commercial development in exchange for commitments for more affordable housing to shifts in zoning and development standards. Property values are important, but so is making sure that there are apartments and homes for the lower-level employees whose work greatly affects a city's or a county's quality of life. Everyone has a vested interest in that.