Area government officials yesterday proposed relaxation of tough, new federal antipollution standards planned for the Blue Plains regional sewage treatment plant. Officials said their plan would save up to $120 million in enforcement costs and avoid an immediate moratorium on development in the District and Montgomery County.

The proposal is the latest maneuver in a continuing struggle between local officials, who want increased capacity at the treatment plant, and the Environmental Protection Agency, which wants stringent limits on the amount of pollutants that can be poured into the Potomac River.

Fairfax County acting executive J. Hamilton Lambert, backed up by other government officials who want to squeeze as much capacity as possible out of the existing sewage treatment plant, said yesterday that the EPA restrictions can be eased without endangering continued cleanup of the Potomac.

Jack J. Schramm, EPA's regional administrator described the proposal as "just excellent work. We're looking at that very carefully. It may well have some merit as an interim solution while some long-range planning is done. We are not dismissing it out of hand."

Local government officials drew up their proposal as EPA moves toward issuing the Blue Plains facility a new operating permit, which must be renewed every five years. The new permit is due July 1.

The local proposal was detailed at a meeting that included D.C. Mayor Marion Barry, Montgomery County Executive Charles Gilchrist and Fairfax County's Lambert. Prince George's County Executive Lawrence J. Hogan sent his top assistant, Kenneth V. Duncan.

The EPA first circulated a draft proposal earlier this month that would toughen pollution standards and in effect reduce Blue Plains capacity by 41 million gallons a day.

The local proposal yesterday was intended to counter the EPA plan.

"We have reached an agreement that, I think, precludes the necessity of establishing a moratorium (on new development)," Fairfax County's Labert said yesterday.

A moratorium could result in disruption of part of $1.3 billion worth of commercial development planned in the District, which wants its present construction boom of continue into the 1980s. A cutoff of sewer taps could also imperil Montgomery's hopes of attracting 1 million to 1 1/2 million square feet of prime office space that as in various stages of planning.

EPA wanted Blue Plains' users to include stormwater that enters the District's combined sewers as part of the plant's sewage flow.

Regional officials argued yesterday that if stormwater is counted, they would be robbed of 41 million gallons' worth of capacity daily at Blue Plains. One million gallons is enough to serve the equivalent of about 10,000 people. To replace that capacity, they said, would cost $100 million to $120 million.

The technical document that the regional leaders agreed to proposes that Blue Plains' capacity be raised from 309 million gallons daily to 350 million gallons-by relaxing pollutant standards-to handle the stormwater flows.

In addition to submitting its permit proposal, local officials asked EPA for a "credit" for present treatment of stormwater that would give the region more than 15 million gallons of additional treatment capacity daily-or enough for about 150,000 more people.

Lambert said the credit would be paid back over years through various measures such as water conservation and sealing leaky sewer pipes. He said the credit wouldn't endanger cleanup because many of the committed sewer taps at Blue Plains - which are all counted against current flows-will not be used for years.

Lambert said yesterday that from 1970 to 1979, the daily amount of oxygen-consuming material-the main source of water pollution-that is dumped in the Potomac has been reduced from 163,690 pounds to 109,461 pounds. New treatment capabilities at the Blue Plains plants will dramatically reduce that amount by 1981.

"If that isn't a commitment to the environment, I don't know what is," Lambert said.

Local leaders have argued-and the EPA has acknowledged-that research used to develop pollution standards needs to be updated. Those leaders are confident that a new look at the figures will show that standards do not have to be as stringent as EPA had estimated.