The Washington Suburban Sanitary Commission is receiving hundreds of thousands of dollars in unearned revenues each year by charging its 1.3 million customers for sewerage capacity they never use, a WSSC spokesman has acknowledged.

Although no precise figures are available on the amounts of unearned revenues the WSSC gets, the spokesman, Arthur H. Brigham, said it is "likely" that each of the 202,000 private homes in Montgomery and Prince George's counties served by the WSSC was paying at least $1 or morefor sewerage capacity they never used.

While the extra costs to the individual customers may be nominal, the price of installing an additional meter to precisely measure use could cost homeowners at least $113 on a one-time only basis, Brigham said.

Now under study by various WSSC rate review committees are plans to resolve the inequity, although a change in rate structure is not anticipated until next year the earliest, he said.

"It's a real proble. We don't know what to do about it," Brigham said.

The problem exits because of the way the WSSC bills its customers for water and sewer use, he said.

The private homes, apartments, and offices serviced by the WSSC are each currently charged 65 cents per 1,000 gallons of water that flow through the site meter, and a sewerage use fee of 95 cents for each 1,000 gallons of water as measured by the water meter, he said.

The problem of extra fees charged for sewerage use arises when wter comes into the home but does not flow out through the sewer. This most often occurs in the summertime when water used outside buildings on lawns, gardens, and for car washing flows directly into the ground and not through the user's sewerage system, Brigham said.

"We don't know how much water goes intothe ground and how much goes into the sewerage system," Brigham said. So the agency continues to bill its customers as if all the water flows out through the sewerage system at each location, he said.

Brigham said the agency would sell customers the meter that measures sewer use for $95 each, plus a $10 inspection fee. Installation fees for a plumber are extra, he said. Additionally, the WSSC charges a yearly $8 meter service fee for the second meter.

A consumer using a hose with a 5/8ths of an inch diameter nozzle for one hour on his garden would use up about 1,000 gallons and pay the agency 65 cents for water use and 95 cents for sewerage capacity use even though most of that garden water never left the yard, Brigham said. The installation of a second meter might save the customer 95 cents for his one hour's watering, but the $2 quarterly meter fee would eat up his savings.

"Only really big water consumers, those who use an extra 25,000 or 30,000 gallons during summer, benefit from the second meter," he said.