How to Drain and Vent a Kitchen | This Old House

Richard Trethewey shows Kevin O’Connor a traditional drain and vent configuration as well as a bow vent.

Richard Trethewey shows Kevin O’Connor two common rough plumbing conditions in the Lexington kitchen: a main sink that has a traditional drain and vent configuration, and an island prep sink, which requires a bow vent in order to work properly.

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This Old House is America’s first and most trusted home improvement show. Each season, we renovate two different historic homes—one step at a time—featuring quality craftsmanship and the latest in modern technology. We demystify home improvement and provide ideas and information so, whether you are doing it yourself or hiring out contractors, you’ll know the right way to do things or the questions to ask. Our experts including general contractor Tom Silva, plumbing and heating expert Richard Trethewey, landscape contractor Jenn Nawada, master carpenter Norm Abram, and host Kevin O’Connor give you the tools you need to protect and preserve your greatest investment—your home.

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How to Drain and Vent a Kitchen | This Old House

[larrymoore]

What I like about this video is how Richard shows and explains the vent system in this area of the house.

[WillNGo]

These videos are just so intelligent, well presented and practical. As an old guy who's worked every aspect of construction these videos are a refresher, but I always learn something new from them. Well done This Old House.

[SportsFan]

Exquisite explanation. I spotted the potential problem of a blockage quickly but didn’t know how to solve it. Richard explains so well. Nice vid

[tsavoca]

Where I’m at (Cincinnati) clean outs are required under the sink and at the wall. I guess not needed here but I like it as a cheap way to get piece of mind; allows you to quickly clear the vent portion from either direction in case of a blockage.

[scotttovey]

It's almost as though Richard is intentionally training plumbers with these short tutorials.

[Btu]

For a small house 900sf2 with one bath and laundry in the garage, can I tie all the vents in the attic to a single vent 3" and direct it out to the highest point of the side of the house so there will be no penetration through the roof since I am planning on installing metal roof?

[JtotheRizzo]

What kind of PEX piping was that? It seemed more flexible than Uponor (Pex-A) or Zurn (Pex-B)

[TampaMaximumMike]

Note to self, never have an island sink.

[sontien]

Than you!!! Sir! Practical, Intelligent

[mrswolls]

Is pex becoming the norm for residential plumbing?

[blobscott]

The top of the loop vent should be assembled with two 45 degree bends with a single 90 degree at the top (i.e. between the two 45s). This is so there is no horizontal section that could hold any standing water/gunk should the vent flood. What is shown here has two 90s connected with a short straight stub. Probably not a big deal, but not really the officially correct way - and may not pass code in some areas.

[dosadoodle]

This is such a clever solution for that problem. It also seems like it could be useful for a sink below a window, and if that bow is run above the top of the sink / countertop height, then water cannot back up to the top of the bow -- the sink would overflow before that happens. (I'm here looking for the best solution to my sink below a window venting problem. :))

[adamcronin]

Is that a proper loop vent in your state? Not mine 2 45’s and a 90

[andrewrodriguez]

So if a vent is lower than the flood level of a fixture, the vent will completely fill up or only fill up to that level?

[mrpickle]

Island drain is supposed to have a clean out and the foot vent also. The loop vent should have a 45 ftg in between the two 90's.

[exportedafrican]

That’s so complex I’m starting to think about going back to an outhouse.

[BC-hrof]

discuss an alternate to the island vent … Oatey manufactures a ‘sure-vent’ as an alternate .. please demonstrate … thanks.

[albertodelgado]

Arent there (east coast) indirect drains code for kitchen sinks? Or is that just code for commercial applications?

[bgraf]

Why couldn't you just add an air admittance valve under the island?

[grumpyR]

How far can the kitchen sink waste run to the main vent