These traps are important and sometimes are confused with an S-trap. The shower and toilet are connected to the sanitary sewer system. Yet, you cant use a sanitary tee in all drain applications. Catching a whiff of sewage in your home is never pleasant, and left untreated, it could cause costly damage and negative health impacts to your family. When a trap is installed on a fixture that is not routinely usedsuch as a floor drainthe eventual evaporation of the water in the trap must be considered. But overall, its more dangerous not to conform to the code because of the possibility of the sewer gas leaking and returning to your home. A P-trap is a plumbing device that is commonly used in residential and commercial plumbing systems to prevent sewer gases from leaking back into a building. When it comes to repairing or replacing a P-trap, homeowners may wonder whether to tackle the job themselves or hire a professional plumber. How much water stays in the toilet trap? | Terry Love Plumbing However, on average, a P-trap can hold anywhere from 2-4 cups of water. The diameter of a sewer pipe is much wider than that of the drain. A botched repair job can lead to water damage, leaks, and other costly problems that may require professional help to fix. Dishwashers or multiple sinks in the same area spell trouble for a lone P-trap. In heating systems, the same feature is used to prevent thermo-siphoning which would allow heat to escape to locations where it is not wanted. Otherwise, avoid running the multiple water-using appliances and fixtures that share a P-trap at the same time. I suspect that the floor drain is eventually evaporating the water in the p-trap, and I'm getting sewer gasses coming up. And what happens if it dries out? Additionally, the p-trap may be leaking, or something may have drained the water in the p-trap. edwardsplumbingllc.com. If a P-trap dries out from lack of using the fixture its attached to, sewer smells and gases begin to infiltrate your home. There are a number of causes of this smelly problem. What Is a P-Trap? | Family Handyman There is the risk of contaminating your home water and sprouting a deadly waterborne infection, and thats not all. Ideally, the vent should not be farther than 6 feet from the weir of a standard trap. The weir is where the water either starts or stops going down the drain after the trap. Lastly, the P-trap needs to be the correct size for the drain of the fixture.