Washington voters preparing to decide whether the city should have a bottle deposit law have been bombarded with claims and counterclaims about the effects that the measure known as Initiative 28 would have if approved on Tuesday.

But that's nothing new. Even in states where bottle laws have been in place for years, some questions about the impact of deposits have never been resolved.

Of the nine states that have bottle deposit laws -- Connecticut, Delaware, Iowa, Maine, Massachusetts, Michigan, New York, Oregon and Vermont -- several have examined the impact of deposits, with the studies in New York and Michigan widely regarded as the best documented.

A review of available state studies shows:

Residents in bottle bill states overwhelmingly approve deposits despite the inconvenience of saving bottles and cans and returning them to stores.

Voters in Michigan, for instance, initially approved that state's bottle law in 1976 with a 64 percent majority. A later poll showed that popularity of the law had risen to 86 percent. In New York, which enacted its deposit law in 1982, a survey two years later showed that 80 percent of state residents who were questioned gave a rating of either "favorable" or "very favorable" to the law.

Deposit laws have a profound impact on litter caused by beverage containers.

"The bottle bill has done exactly what its proponents said it would do. It has cleaned up litter," said Clayton Davis, administrator of Maine's deposit program. "All you have to do is cross the line into New Hampshire and see the difference."

Estimates on the reduction in container litter range from 69 percent to 83 percent, based on surveys of roads in the states. But how bottle laws affect the total litter picture -- containers plus other trash -- is a more controversial question.

Some states have said that total litter was cut from 34 percent to 47 percent. In one Michigan study, though, the estimate varied -- from a 10 percent increase to a 10 percent decrease -- depending on whether adjustments were made for the effects of rain on road traffic.

New York's study had no measure of litter before the bottle law took effect. Instead, the study relied on a comparison with Pennsylvania, a nondeposit state, and officials concluded that the resulting figures on total litter were too unreliable.

Retail stores, especially the smaller ones, are hit hardest by bottle bills, with a lack of storage space and increased need for pest control the biggest complaints.

The handling fee that stores receive for taking back bottles and cans for redemption -- usually 2 cents per container -- is barely enough to cover the cost of making extra storage space and paying employes to sort the containers. In some areas, owners of small stores have received relief from redemption centers that specialize in collecting refundable containers.

Many store owners complain that they get too many dirty bottles, despite provisions in most laws that they need accept only clean ones.

Prices on some beverages go up -- in some cases dramatically so -- after deposit laws are enacted, but exactly why is unclear. Only three states -- Iowa, Michigan and New York -- have ventured to examine price changes in depth.

Those studies have found that prices for beer are more likely to increase than those for soft drinks. Soft drinks are more competitive, and beer drinkers apparently buy their preferred brand regardless of price.

In Michigan, beverage prices went up 9 percent to 10 percent, adjusted for inflation. But surveys found that while prices for national premium brands of beer jumped, prices for cheaper beers didn't change at all. A 1984 survey of 72 stores by the New York State Consumer Protection Board found that beer prices statewide increased 18.3 percent, while changes for soft drinks were "insignificant."

In New York, as in Michigan, national beer brands were most affected, with large price differences from store to store. Skeptical state officials said changes in prices may have resulted partly because brewers had withheld increases for months until after the deposit law was enacted.

Stores near state borders have lost sales after bottle laws were passed, but in many cases buying patterns may have been influenced by changes in the legal drinking age.