Double sink drain install (2024 Update)

I'm installing a double sink. The basins are 20 gallons each and the drains are about 8" apart. I will be installing a 1.5" PVC vent around the room near the top of the studs to serve all the fixtures. There are two ways to connect the sink drain--a single trap or separate traps for each basin. If I install separate traps, I could install a separate vent for each trap. I want to eliminate any possibility of waste water draining from one basin to enter the other (empty) basin. What is the best configuration?

Reply to
Phisherman
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seperate traps always better. are you certain a 1.5 inch vent is enough?

Reply to
hallerb

Not sure. The area is already plumbed with a 2" drain and 1.5" vent (for a bathroom). My intent is to install a large shower and laundry hookups as well. This house was built in 1992--does current plumbing code require 2" vents? If so, I'm concerned about drilling holes through the studs which are only 3.5" wide. 2" PVC will require 2.5" holes through these studs.

Reply to
Phisherman

could transistion thru studs to copper or other thin wall material just thru studs.

we need a plumber here, with all the new stuff your adding 4 inch main vent might be necessary.

venting prevents siphoning of traps.

with such a small vent diameter showering while doing laundry might suck the other traps dry, allowing sewer gas into home. I have a old friend who found natural gas in his home, after a leak a quarter mile away got in the neighborhood sewer line and somehow found its way into his home.

he opened door and left. smart fellow a retired fireman.

he had a cracked main trap and a leaking sink trap, leaving a nice escape path for the natural gas. his home could of exploded.

you getting a permit for this work? if not it might come back to haunt you at home resale time.

Reply to
hallerb

buffalo ny: who/what/where/when/why/how: who is stopping you from reventing to the 4" soil stack? what is the trap size don't go bigger than the kitchen 1-1/2" or the draining will fight an oversize trap. where are we, in the kitchen? when you run all the fixtures simultaneously in the house thru a slow sewer why not check the local requirements, sometimes for the cost of a plumbing inspector will get you amazing info to help you. how far above/below grade, how much water is pumped out so much faster on many of the newer machines, how much pitch is needed on your upcoming addons and so on. first look at:

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see good vent specs at:
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description info and links at:
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see:
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Reply to
buffalobill

There is no 4" soil stack.

Basement.

Thanks for these links.

Reply to
Phisherman

Hi, When I look at ours in the kitchen one trap with 2" vent. We have a dish washer and garburator as well draining into it.

Reply to
Tony Hwang

Does the building code call for 2 traps for a double kitchen sink ?

Reply to
Omer

In which jurisdiction in which country?

Reply to
Retirednoguilt

I wouldn't think so but:

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sell them.

But at

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one guy, of unknown sanity, actually says that one trap is safer! And he speculates on a rarely encountered reason.

Another guy quotes something that looks like it comes from a code:

P3201.6 Fixtures shall not be double trapped: [Exception 2 to the normal rule] A single trap shall be permitted to serve two or three like fixtures limited to kitchen sinks, laundry tubs and lavatories. Such fixtures shall be adjacent to each other and located in the same room with a continuous waste arrangement. The trap shall be installed at the center fixture where three such fixtures are installed. Common trapped fixture outlets shall not be more than 30 inches (762 mm) apart.

Although he doesnt' give a source, Googling the first two lines of this shows where he got it,

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course this is from the International Code Counsel and we all know that only the US codes are of any value, that international codes are dominated by communists and leftists and Europeans, even when the code is in English. So whatever it says, one should do the opposite. I learned this from my Repubican County Chairman, and I pass it on to you. I haven't time now to look for a code from your country, but I'm sure if you live in a decent country that it says the opposite of anything the Internationale would say.

Reply to
micky

The jurisdiction is in Toronto, Ontario, Canada'

Reply to
Omer

Reply to
Clare Snyder

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