LESLIE: Well, when it comes to the plumbing in your house, how much do you really know about it and do you have to know about it? I mean other than the fact that it makes weird noises and hopefully it works when you need it to and want it to …
TOM: That’s all that’s really important. (chuckles)
LESLIE: Yeah, seriously. If things go where they’re supposed to go and water comes out of where it’s supposed to, then hooray; we all win.
TOM: Life is good.
LESLIE: But what happens when it doesn’t work properly and what about this mysterious venting that I hear so much about?
TOM: Well, you know, if your system is sluggish, the cause could be the venting and here with some tips on how to straighten that all out is Kevin O’Connor, the host of This Old House, and plumbing expert Richard Trethewey.
And Kevin, there’s a little bit of mysterious alphabet soup to this whole process because we’re really talking about something called the DWV.
KEVIN: That’s right. Residential drainage systems are often abbreviated DWV for drain, waste and vent. Most people understand the drain and waste part but they may not understand why a plumbing system has to be vented.
RICHARD: Well, venting is absolutely critical to any drain system. It has to breathe. You know, when water goes down that drain, the air that’s inside that piping, before the water went down, has to go somewhere. Think about it. Imagine putting your finger on the top of a straw full of water. That water will not drain out of the bottom unless you let the air into the top.
So, when a system is not vented fully or properly, you can have gurgling and slow draining of sinks, tubs, toilets. You also might get the smell of sewer gas if the poor venting causes a trap to lose its seal.
KEVIN: So a lot of times we see the vent pipe going through the roof. But do you always have to penetrate the roof?
RICHARD: Well, usually the venting of a new fixture can tie into the existing stack then exit the roof but not always. In some circumstances, you may be able to use a special one-way vent called an air admittance valve. It allows you to vent a system from inside the house; perhaps in a vanity, kitchen island or even a basement. These valves satisfy most plumbing codes but not all.
KEVIN: Alright. If you want to learn more about the science of venting, visit us at ThisOldHouse.com.
TOM: Or if you just want to vent, you can go to ThisOldHouse.com and tell us your plumbing story.
KEVIN: (overlapping voices) That’s right. (chuckles)
TOM: Richard Trethewey, Kevin O’Connor, thanks for stopping by The Money Pit.
RICHARD: Thanks, Tom.
KEVIN: Good to be here.
LESLIE: Yeah, and you know sometimes I find that the bathroom is actually the best place for me to vent. (Tom laughs) I just shut the door; I let it all out; I go screaming, complaining about everything that’s going on at the house. And you know what? I actually feel much better.
TOM: I’m glad that works for you. (both chuckle)
Well, for more tips on plumbing systems and so much more, be sure to watch Kevin and Richard on This Old House and This Old House is brought to you by GMC. GMC – we are professional grade.