Washington Gas Light Co. asked yesterday to increase rates by 8 percent in Maryland and by 10.2 percent in Virginia. The company said that the rate hikes would produce approximately $43 million in new revenue if granted.

Just two weeks ago, WGL asked the D.C. Public Service Commission to allow it to add 13.23 percent--or $26 million annually--to District customers' bills.

WGL seeks a $23 million increase in Maryland. If granted, that increase would add $5.62 to the average monthly bill of $70.03 for a customer who heats with gas. The request for $19.8 million in Virginia would add $7.16 to the average month bill of $70.21 for a Virginia heating customer.

The company said it needed increased revenue to cope with inflation and higher labor and interest costs. The rate increase, if granted, would take effect in 1983.

The Virginia State Corporation Commission approved a 4.98 percent--or $80.5 million--temporary rate increase yesterday for Virginia Electric Power Co. that will go into effect May 1.

The figure was less than the 5.9 percent--or $96 million--increase Vepco had asked for under a new procedure that allows rates to go into effect in 30 days, with provisions for refunds if the commission's final decision is to grant the company a lower amount. Vepco said it needed increased revenues to compensate for the erosion in earnings because of inflation last year.