PSA is a chemical made by prostate cells. They draw some blood and send it to a lab. Ideally it should be under 2. Used to be uder 4, but they lowered it.
Try this:
http://psa-rising.com/med/info/psa.htm
Keeping the 'pipes clean' doesn't have anything to do with it.
They usually do a biopsy if the PSA is high or it is rising over several tests.