my German Shepard started this when she was barely 3 yrs old. When it started the vet said she did have a UTI and we treated that but the leaking continued. The vet said it was urine leaking and that larger dogs tend to have lazy sphincter muscles (which are the muscles that control urine flow). Her fluid too was clear and didn't smell, until it dried. She was put on a pill. At first twice a day but we were able to cut down to 1 a day after a couple of weeks. As long as we remembered her pill every day she had no leakage. If we missed even once, she leaked. Your dog's been lucky that this problem is only coming with old age. Take her to the vet but this is probably the problem. This lack of muscle control can make them prone to bladder infections and UTIs so she may have one when oyu take her in. As long as the leaking is controlled there's not much risk of infection.