Understanding how your home plumbing system works can make minor and major repairs seem less stressful. You may even be able to fix minor problems yourself without having to hire a plumber. Drainage Traps - ‘S’ shaped pieces of pipe that allow water to pass through during drainage, but prevent sewage gases from gaining access into your home. maytag refrigerator water filter All sinks should have ‘S’ pipes. Bathtubs usually have drum traps. Toilets have built-in traps. If you notice fixtures in your home that do not have traps, they should be put in place as soon as possible. Water Meter - this meter monitors how much water you use each day.