A five-year moratorium on hookups of new natural gas customers in the Virginia suburbs was ended yesterday when the state corporation commission gave Washington Gas Light Co. permission to take on new customers.

The ruling makes gas available for 3,300 residential and small commercial customers in Alexandria and Falls Church and in Arlington, Fairfax, Loudoun and Prince William counties.

The first to get natural gas will be customers on a waiting list that Washington Gas has been keeping since 1972, when the energy crisis led to a ban on additional gas use.

The Virginia Coporation Commission order said the natural gas "supply particularly for Washington Gas Light has stabilized and there appears to be sufficient gas to provide service" to additional customers.

Energy conservation has cut gas consumtpion, as has attrition of customers, during the five-year moratorium, the company said.

Gas supplies from interstate pipelines have rebounded, and this spring WGL's main pipeline, Columbia Gas Transmission Compnay, will begin importing liquified natural gas at Cove Point, Md.

The West Virginia utility regulators had already permitted Washington Gas's Shenandoah Gas subsidiary to resume hookups in the Martinsburg, W. Va., area. Shenandoah was given permission yesterday to take on 150 additional customers around Wichester, Va.

The District ot Columbia Public Service Commision this week completed hearings on a request to connect 3,000 new gas users in Washington, but has made no decision. Nor has the Maryland PSC ruled on a request to add 4,300 customers in the Maryland suburds.

In what the gas company calls "a test of public acceptance" it is seeking to expand its customer base by about 2 percent, equivalent to adding about $5 million a year to its 1976 annual revenues of $270 million.

A WGL spokesman said hookups of new customers could not begin before spring.

The company will notify customers on its waiting list that gas is available, then will fill application filed since new hookups were requested in October, will finally will fill additional orders on a first-come, first-serve basis.

WGL officials said yesterday they had not counted their waiting list to see how many customers were awaiting service.

The Virginia ruling limits new commerial customers to those using no more than 50,000 cubic feet of gas a day.

It also gives the gas company permission to provide present commercial customers with additional gas - up to the same limit - without counting against the 3,300 total.