Washington Gas Light Co. yesterday proposed a 22.3 percent increase in residential rates for natural gas service in the District as part of a rate request that would shift more of the burden of paying for upkeep of the gas distribution system onto residential customers.

The plan -- one of two rate proposals submitted by the company -- was immediately attacked by the D.C. Office of the People's Counsel, which represents utility customers before District regulators.

The company said it hoped that by reducing the size of the increase to large commercial customers, such as office buildings, to 4.9 percent, it can encourage greater use of natural gas by large customers and win new commercial customers that might otherwise install electric heating.

"Large users pay a much larger share than do small users for the {upkeep of the} distribution system" under the current rate system, said Jack Keane, vice president of WGL. "It's fair to distribute it more equitably and send the right price signals so larger customers use more natural gas. It is also the customers who could potentially use gas that we want to attract."

The utility also submitted a parallel rate request in a more traditional form that would spread a 15.5 percent rate increase evenly among all District customers. WGL will ask the D.C. Public Service Commission to choose between the two plans.

Company officials said they also expected to file rate increases for WGL's suburban Maryland and Virginia divisions later this year, but it could not be determined whether the company would structure those requests as it did the District proposal. WGL serves about 600,000 customers in the three jurisdictions.

The request for an increase comes as conservation programs, more fuel-efficient appliances and competition from other energy sources are reducing natural gas use.

Washington Gas Light said it needed the rate increases to help pay for the rising cost of service to its customers, but the District's people's counsel, Frederick Dorsey, questioned whether costs had risen that much since the utility got its last rate increase, 5.8 percent in September 1986.

"I'll certainly have to read the company's application because I can't imagine how they could possibly need the money," Dorsey said.

Suzanne Crowell, a spokeswoman for the office of the people's counsel, also questioned the company's rationale for proposing to put more of the increase on residential bills. "This is just an excuse to shift costs to the small residential and commercial customers in an effort to retain large customers who don't have a choice of fuels but could eventually make provisions to switch," said Crowell. "They still haven't come up with any proof that these large customers are about to go anywhere."

Crowell said part of WGL's problem with winning new commercial customers is "poor marketing efforts" among developers.

The D.C. Public Service Commission said it would scrutinize the request closely. "Any business is susceptible to price increases, but you also have to focus on the productivity gains that customers and regulators can legitimately expect of a company," said Howard Davenport, the commission's general counsel.

"I am not at all sure that the commission is going to buy into the company's argument that it needs to shift those costs to residential customers," Davenport said. "Even assuming some validity to the company's argument, this commission historically adjusts rates in very small increments."

The first part of the utility's two-part rate request was a fairly traditional request for a 15.5 percent rate increase spread evenly among residential and commercial customers, under which the typical monthly bill of a residential heating customer would increase by $10.34 a month.

The second part of the proposal, containing the change in how the increase would be allocated, was in the form of an amendment to a pending request to the PSC for a complete restructuring of the company's rates.

Under the proposed new formula, the typical monthly bill of a residential heating customer would increase by 22.3 percent, or $14.85 a month. Large commercial customers would see their rates go up 4.9 percent, or $35.93 a month.

This proposed rate structure would also favor large customers by providing bulk volume discounts as more natural gas is consumed, in an effort to win over new commercial customers that are tempted to install electric heating, WGL officials said. WGL has been facing increased competition from Potomac Electric Power Co. for new customers, especially among developers who are putting up new buildings, WGL officials have said.

Keane said the new rate structure would send "the right price signal" to customers and encourage them to use this country's abundantly available natural gas supply.

Thomas A. Duckenfield, vice president and general manager of D.C Natural Gas, the WGL subsidiary that serves the District, attributed the utility's need for a rate increase to higher costs of capital and investment, increased operating expenses and decreased gas sales.

He said the decline in sales was due to aggressive conservation among residential and commercial customers and the installation of more efficient gas appliances.