IMHO, Never.

I have a Chesapeake Bay Retriever who does better IN the water than out....its like her source for super power. She can hardly stand to not be in the water, even if she has to break ice to get there.

My Chesapeake Doesnt go in the pool. She has been trained not to and we're happy about it. We trained her since she was introduced to the pool.

It might sound fun to have a puppy in the pool, but a full grown dog is a liability and more trouble than anything else.....not to mention very dirty.

If you raise that puppy thinking he can pounce in the pool, you'll never get him to stop.

Dont get me wrong, we love our dog and we take her to the lake and river all the time....but our pool is for people. Our dog also seems very happy to watch us swim and hang out around the pool.