THE AVERAGE RENT of a two-bedroom apartment in the Washington area has risen by $400 since 1977, up to $680 per month in Northern Virginia. Affordable housing is not only increasingly difficult to find, it's also hard to keep. Developers have bought massive amounts of low- to moderate-income apartment complexes in Arlington and Alexandria to make extensive renovations to lure higher income renters. That could have resulted in further economic segregation and the complete displacement of thousands of the working poor.

But a laudable series of agreements, combined with strong legal pressure on behalf of the current tenants, will allow as many as 370 poor families to remain in their apartments at Lee Gardens in Arlington and in the Arlandria section of Alexandria. First, lawyers from the NAACP, the National Housing Law Project, Northern Virginia Legal Services, Georgetown University's Institute for Public Representation and the D.C. law firm of Roisman, Reno and Cavanaugh fought the planned evictions in federal court. Alexandria officials persuaded the U.S. Housing and Urban Development Department to offer 348 rent supplement vouchers and certificates. That encouraged developers John Freeman and Conrad Cafritz, who had purchased the Bruce Street apartment complex in Arlandria, to set aside 68 of their units for current tenants. Alexandria will also be offering $600,000 in city funds to help pay rent for poor tenants.

The tenants' lawyers and another developer, the Artery Organization, have an agreement in principle for another 104 poor families in Artery's newly purchased Dominion Gardens apartments, also in Arlandria. Artery also purchased the Lee Gardens apartments in Arlington County and has agreed to sell 364 of its 900 units to local officials in a plan to save 200 apartments for poor tenants. Further, the Arlington County government persuaded the Virginia State Housing Development Authority to provide $33.6 million to buy and renovate these apartments. More federal vouchers and certificates are planned to help pay the rents of the 200 tenants.

These are clear signs that wholesale displacement of the poor can be avoided when state and local governments work together with developers and with the tenants and their lawyers. But federal housing assistance is still badly needed. As housing markets continue to tighten, that need will continue to grow.