Maggiedog: I have a husky/shep with the exact same conditon. For a while it was so exasperating trying to pinpoint the problem. She too initially had many UTI's but these were a RESULT of the condition that predispose dogs to this type of incontinence not the cause. (Incomplete emptying of the bladder frequently leads to urinary tract infections) Most often, they will leak urine while resting or asleep, totally unaware of doing it. It is a condition most frequently seen in spayed females. After their surgery, they have a hormonal shift that causes them to involuntarily leak urine. At first I did what you did. Urinalysis, ultrasound, etc. When all anatomical reasons were ruled out, such as ectopic ureter (wrongly positioned) incompetent sphincter, etc., my vet tried her on one of two medications frequently given for this condition. One is a hormone therapy; the other is a drug called "Phenylpropanolamine." It is a drug often found in many human medications, and has been in the news of late. The side-effects however are not the same for dogs as for humans, so don't be concerned if you hear negative things about it on TV. (It may, in rare cases, predispose young adults
to high blood pressure and stroke. NOT DOGS)
Anyway, after years of frustration over this problem (Cody was also so embarassed when this happened) the medication was like a miracle!! She gets 50mg 2x daily and only once a month or so she may have a teeeny, tiny bit of dribble. Many dogs I know are on this medication with the same positive result! Talk to your vet about it and don't despair! No one was a bigger doggie-dribbler than my Cody! Not she is leak-proof!