Slot machines in Washington are some of the loosest in the country. At most casinos, the house edge is 2.5-3%. This means that for every $100 that is wagered, the casino will make $2.50-$3.00.
In comparison, at most Nevada casinos, the house edge is closer to 1.5%. This means that for every $100 wagered, the casino will make only $1.50-$2.
The reason why slots in Washington are so loose is because of how new the state is to gaming. The state has only had legal gambling since 1983, and as a result, there are only a handful of casinos currently operating in the state.
This lack of competition has led to casinos being able to offer lower house edges in order to lure players into their establishments.