by Ben Wanner of Pro Service Mechanical
Have you ever noticed the smell of sewer in your home? There is a very good chance you may have a problem with the venting arrangement of your home's waste plumbing system.
Have you ever wondered what those little black pipes are coming out of the roof of everyone's house are for? They are the stack vents of your homes plumbing system. These pipes serve a couple purposes. Firstly they help to vent sewer gases out of the public or private septic system. The other function of these vents has to do with the curved pieces of pipe you can see under your sinks, bathtubs etc called traps. We first need to understand that the traps are being filled with water from the fixture and this creates a seal that keeps sewer gases from getting out of the septic system into our home. These pipes help keep that seal and we will find out how but first we need to understand the basic parts of the waste plumbing system in our home and what they do.
- The Trap (seals out sewer gases from entering the home)
- The Trap Arm (carries the plumbing waste from the trap to the soil stack)
- The Vent "dry vent, wet vent, stack vent" (used to break the vacuum that is caused by waste water filling the entire pipe)
- The Soil Stack (the main stack below the stack vent that carries sewage and waste water to the public or private septic system)
It is very important that the vent be placed not to far away from the trap on the trap arm. The reason is if you can imagine the water going down the sink, as some water gets left behind in the trap to make the seal the rest continues on. If this water fills the entire pipe either because of the distance or because the pipe suddenly pitches downward then it can create an air vacuum. This vacuum will cause water to be pulled out of the trap and break the trap seal.
If the trap seal breaks we can have gases from the sewer system enter the house. Placing a vent in the proper location will stop this from happening as it will break the vacuum and leave the water in the trap. Sounds simple enough right? Well there are many factors to ensuring this works correctly which include
- the trap arm distance
- pipe slope
- wet venting arrangements
- multi story venting arrangements
- island sink venting
- and more........
If this is not planned and executed properly and not to current plumbing code we will have likely have problems. There is a lot that a professional journeyman plumber needs to know to do this in a new home or renovation situation.
All to often we see problems when a homeowner or untrained handyman undertake a bathroom renovation, move or add fixtures or develop a basement without a plumbing permit.
If you see an installation such as this photo below in your home, you definitely have a problem.
If you have any questions or would like to talk to us about problems or alterations with your plumbing system, give the pros a call at Pro Service. Just click here for our phone or email Contact us