Uhhhh it rarely ever is free of parasites, giardia and bacteria. Your state's conservation department should have a list of safe swimming areas but you will likely always encounter giardia and parasites.
Jane, leptospirosis is a big concern for dogs that come into contact with river or pond water. There is a runoff after the spring thaws when the snow melts, and lepto is spread from the urine & feces of wild animals being present in bodies of water. Giardia can be passed this way too, but lepto is much more serious & is increasing in many areas. I don't think there is any way to be sure; I was told in no uncertain terms to have Jack vaccinated against lepto if he is going to be coming into contact with rivers, ponds, streams, etc.
Your dogs will love this pond! The lepto vaccine is usually given on its own-with no other vaciines-so the timing is perfect. It is a serious disease from what I hear-worse than parvo-so why not protect our dear babies.
Our dog goes to a conservation area which is designated as an "off leash" area just for dogs . He runs with nine other dogs that are in his "group" through bogs, streams, and shallow ponds. When I go to pick him up, he is soaking wet, tired and SO happy. I had him vaccinated for everything including lepto. When he dries off, I brush him and check for rashes or anything unusual. I hope he doesn't pick up anything like parasites etc. but I wouldn't trade this experience for anything. He whines and cries in excitement when he knows he is going with Wayne-the dog group walker. But now that I have read the other posts-I'll check with the vet on other preventative measures.