The town of Lovettsville will soon survey its 613 residents in an attempt to prove to the federal government that "our median incomes are below average for the region . . . which could qualify us for a larger grant for our sewer system" repairs, Mayor Richard Hummer said this week.

The poor-mouthing in Lovettsville is now being heard across Northern Virginia as many small towns attempt to qualify for state and federal grants which bypassed the "wealthy" region last year.

In a separate action, the Northern Virginia Planning District Commission is now seeking funds needed to finance a refining of the 1980 census figures, which showed Northern Virginia with a median family income of just over $30,000 a year. That helped make Washington the nation's wealthiest large metropolitan area with $27,500 median income.

"Many small towns here could have as high unemployment and low average incomes as towns in Southwest Virginia," according to NVPDC spokesman Thomas Brannan. But no one would know it now, since family income statistics are not broken down on a town by town basis, Brannan said.

Last year nine Northern Virginia localities applied for community development block grants, which are federal funds given the states for distribution. "But noboby here got any and we think one reason was we didn't have refined census income figures," said Brannan.

Lovettsville is seeking $220,000 for improvements to its sewer system under a rural communities grant program of the Department of Agriculture. But the grant will depend on a number of factors, including the town's median income and its indebtedness, said Hummer.

The town needs $240,000 to repair and slightly expand the sewer system, and would have to put up an additional $20,000 if it gets the maximum $220,000 it is requesting.

Whether Lovettsville will prove to be poor enough to be eligible for the grant program, however, is questionable. The median family income of a community is supposed to be below $13,000 a year for the Agriculture Department program, according to the engineering firm of Dewberry and Davis, which is assisting the town in the initial stages of its application.

Mayor Hummer said he thinks the town's median income may be below $15,000, because "more than one fourth or our residents are elderly or on fixed incomes.