There are simple ways to manage something many of us will eventually encounter with our older Kerries.
Do a cysto (drawing urine from the bladder) and Culture and Sensitivity.
The cysto is absolutely no big deal, they do not feel a thing, and it's over in a second. Scamp had one a month for 18 months with no ill effects. Depending on how sophisticated your vet clinic is they can do an ultrasound guided cysto, but it is very straightforward. A culture is more expensive than a UA, and the only other problem is that it takes 4-5 days to get results back and in this world of instant gratification that seems forever. However it will give you the only accurate information.
I would try homeopathic/herbal remedies. Many people have had good success going this route. Marina Zacherias has supplied me with a program, however there I know of several vets in the SF Bay Area putting patients on a different herbal program with good success.
If that failed I would try PPA (Phenylpropanolamine). It must however be the time released PPA and be given 2xdaily to remain in the system long enough to be effective. PPA is effective in 85 to 90% of cases, regardless of the root of the problem. PPA has less side effects that estrogen. When they took it off the human market it became more expensive and more difficult to get a hold of, but I get it through UCDavis with no problems. Heddy and Scamp have been on PPA for years with no ill effects. At times, like the coming of hot weather, Scamp will have leaking and I put her on other remedies I get from Marina.
My UCDavis vets only recommend Estrogen after all else has failed.
Managing incontinence with two dogs has not been a problem at all. Sometimes when Scamp is sick with a stomach problem, she'll have some leaking problems. We have a supply of kiddie pullups we can use it we are experiencing a problem, but those times are few and far between.