THE REFUSAL of the Virginia Supreme Court to delay enforcement of Fairfax County's sensible controls on throwaway bottles and cans seems to be having an encouraging effect already on similar efforts around the region. Though the justices' decision only clears the way for a hearing on the merits of the case in the county circuit court later this year, officials in other jurisdictions are buoyed by the break-through. That, in turn, should be good news for those county residents now experiencing temporary difficulties adjusting to the new ordinance - for the more jurisdictions that make the switch, the simpler the shopping will be.

The Loudoun County board of supervisors, for example, has just voted unanimously to advertise its latest plan to adopt an ordinance covering both soft drinks and beer when the board meets on Oct. 3. An earlier Loudoun ordinance was overturned last year when a circuit court judge ruled it unconstitutionally vague and found that it conflicted with state Alcoholic Beverage Control Board laws. Loudoun officials now say their rewritten version meets the criticisms and includes beer on the grounds that the ABC Board controls a container's contents but that the local jurisdiction has the right to control the container. We hope this interpretation of local option in Virginia proves correct.

In Arlington, county board member Ellen M. Bozman says the latest court decision makes it likely that the county board also will advertise container legislation for a public hearing. The board meets Saturday and action on this front would be a welcome step. In Alexandria, the city council is expected to consider a request by the Fairfax supervisors of all local governments in Virginia to enact deposit requirements.

That''s precisely what's needed to make the controls work with a minimum of hardship throughout Greater Washington. Right now, there are some difficulties in Fairfax, since the county has turned out to be the pioneer in the shift away from the cost, waste, mess and senseless consumption of energy and natural resources connected with the manufacture and recycling of glass and metal to be sold and tossed out again.

For one thing, the vending-machine people aren't sure how to adjust to the change in Fairfax. But if returnables (including cans with the proper refund stickers) were readily available, sold and accepted throughout the region (just like the old days - remember?), people would find convenient ways to get their nickels back. Paper cups in the machines, while they do make trash, are another possible answer for many machine operations.

For now, however, the throwaway-bottle-and-can lobbyists are likely to help ease the strain so long as they're still in court testifying about how rough life without throwaways can be. Still, smart shoppers are discovering that where the shelves are well stocked with returnables - or the throwaways with the refund labels - selection and savings can go hand in hand. Anyone who may question the savings in buying drinks in returnables should check the price difference on colas and beers sold in returnable bottles in the District.

Sooner or later, in fact, the smart manufacturers, bottlers and distributors will realize that the first ones to take the lead and fill the shelves with returnables stand a good chance of capturing a good slice of the consumer market. In Oregon and Vermont, two states where deposit laws have been in effect for some time, consumers don't seem to be deprived of any of their favorite beverages - although they do seem to be short of much litter that used to desecrate the countryside. Fairfax residents, too, should be able to survive quite well once the transition is given a fair run.