Thats a tough one to answer. There are all kinds of little things to look for. I would definetly check you connections behind the wall on the shower, often. Mine leaked then quit, then started leaking again. Same with the connections under the sink, mine went almost 1.5 years, then all of a sudden they started to drip like crazy one day. All I did with both shower and kitchen connections was to loosen them and re-tighten. My water pump only lasted a year...although its gets very cold here in winter.
Word to the wise...when you leave your coach while camping I would make a habit of shutting off the water pump power. If something decides to leak while your gone it wont be a major flood event.
