How long do they keep dogs before they put them down?

You wait a while. Its first come first serve. Once you get into the doctors office you speak to a vet. So just like any normal place. Why dont yoj surrender your dog to the pound they have a vet evaluate them and then give them a shot if they dog is terminal. Plus its only 10 dollars compared to what the vet might charge, in the hundreds

I think your question was misunderstood. If dog is deemed sick at surrender it can happen pretty quick. If dog is healthy it's usually least 10 days, usually much longer. Many dogs stay a month or so. Depending on age, rescues will adopt dog and try to find a home, all depends on type of dog, age, health, etc ..

Like David said.