What causes a loud swishing noise in my pipes when the water is running It sounds like the water when running a dishwasher. I have lived in this home for 5 years but just recently began hearing it.?

If this is in the drain lines, then there is a small amount of build up, which will happen over time. Watch to insure that the water is draining and not starting to go slower indicating a stopped up line. If this is the water line, look at the water coming out. If it is discolored or frothy air may be mixing in, probably from a problem on the side of the municipality supplying the water.