Venting through the sewers

I'm sure this has been tried, it's just too good of an idea.

Basement growers, why not hook a fan up to a stack cleanout or a floor drain to vent all that smelly air into the sewers?

You would need a way to prevent backflow of course, something like a p trap, but other than that it seems like a good idea. It would be hard to overpower the scent of sewage.

Thoughts? Drawbacks?

I prefer a carbon filter but it may work

May just well lead to an experiment....however, i think most house lines running to the street are 4 inch. You can only push so much air through there. Also, if the air was hot, i think it'd try to rise, and maybe try to go out of the vent that comes out of your roof that's hooked into the drain system (assuming it's not plugged with a bird nest or something

should work with enough cfm's in your fan.

The only drawback i can see is if all the sudden the reclamation people show up to do their random inspection/cleaning of said sewer line, i think they'd notice it reeking of weed and investigate? yes/no? Don't know about where your at, but around here, I'd say like once or twice a year, they come around and check the sewer mains.

I am a legal patient, so security isn't as huge of an issue as it is for others.

I just want to get rid of the smell without another $100+ carbon filter that needs replacing every year and another $30 duct fan. I already have one filter but it's not enough. I want the negative pressure for the whole basement as well, which would help with the slightly stagnant air. With 500cfm pushing down the pipe, it'll go all the way through I'm sure.

The only problem would be fan failure, in which case methane could come up...and I have a hot-water heater there eep


Edit: found a link in the growfaq http://www.growfaq.net/growfaq/1457.htm

Personally I'd try it just to see if it works, very tempting indeed.

i would think they are checking storm sewer drains? and not sanitary, how could you ever get all those people to stop flushing their toilet at once

and i think that the vent would pose a small problem, you would need to to block the vent to stop the hot air from flowing out it also, i wouldn't think that losing the vent would matter since you would basically be pressurizing the line, creating a suck effect at the drain

Murfy, Were i live, they seriously check sanitary lines due to age....They usually only look down the manholes though and don't really do much else

Hmmmm, wouldn't it come back up through your upstairs drains as easily as into the septic or sewage system? bubbles of pot air coming from the porcelain throne, now THATS funny! Also, if you blow out the pee drain, you'll let all the smells come back into the house via the drains while your fan isn't on. Eeek, just buy the filter or get the plans for a DIY filter, they're not all that bad if you get the activate charcoal. Let us know if you try it though!

This IS a pretty sweet idea....

Storm drains and sanitary sewer are two TOTALLY different systems, so smell is NOT an issue when it comes to city workers and pipe inspections....if they open that pipe, trust me, they aren't gonna be smelling weed.

If you hook to the 4" main running out of the house, you'd want to do it with a "4"x4" Wye," and come in from the top of the pipe as close as possible to the point where it exits the house. I don't think hooking into a vent is such a great idea. Most sewer vents are 2" pipe.

A P-trap is not what you're wanting to prevent sewer gas from entering the grow space...a backdraft damper IS. http://www.iaqsource.com/product.php?product=173852


I honestly can't think of why this wont work, but I HAVE been drinking tonight. Negative pressure (although slight) would probably be pulled on the rest of the house's drain/vent system via the venturi principle, but not enough to suck P-traps dry.

Be aware that you cannot effectively vent through a floor drain or other fixture without first drying out the p-trap, but I doubt you have a 4" floor drain in the house.

Another thing...basement?....how old is your house? Does it have an existing chimney? Justa thought.

I say try the sewer. Keep us posted.

KitchenKhemist said:

This IS a pretty sweet idea....

Storm drains and sanitary sewer are two TOTALLY different systems, so smell is NOT an issue when it comes to city workers and pipe inspections....if they open that pipe, trust me, they aren't gonna be smelling weed.

I say try the sewer. Keep us posted.

Click to expand...

I am very aware that they are different....kinda work in close relation to these kind of people actually. I'm all for try the sanitary line though still...

Sorry bro...please don't think i was bein cocky. Just pointin it out. Been seein lots of you btw....in posts and on TV....watched Office Space bout an hour ago

Oh shit, not trying to be cocky either. Yeah, apparently I'm all over doing lots of nothin' . I gotta start making my post less smart @$$/cocky sounding.
Thumbs up for office space too

KitchenKhemist said:

This IS a pretty sweet idea....

Storm drains and sanitary sewer are two TOTALLY different systems, so smell is NOT an issue when it comes to city workers and pipe inspections....if they open that pipe, trust me, they aren't gonna be smelling weed.

If you hook to the 4" main running out of the house, you'd want to do it with a "4"x4" Wye," and come in from the top of the pipe as close as possible to the point where it exits the house. I don't think hooking into a vent is such a great idea. Most sewer vents are 2" pipe.

A P-trap is not what you're wanting to prevent sewer gas from entering the grow space...a backdraft damper IS. http://www.iaqsource.com/product.php?product=173852


I honestly can't think of why this wont work, but I HAVE been drinking tonight. Negative pressure (although slight) would probably be pulled on the rest of the house's drain/vent system via the venturi principle, but not enough to suck P-traps dry.

Be aware that you cannot effectively vent through a floor drain or other fixture without first drying out the p-trap, but I doubt you have a 4" floor drain in the house.

Another thing...basement?....how old is your house? Does it have an existing chimney? Justa thought.

I say try the sewer. Keep us posted.

Click to expand...

Yeah, that's exactly the kind of valve I imagined, like a throttle body.

But what level of CFM fan would I want to put on the 4" stack? I was going to get a home dePOT 4" duct fan for 250cfm because they're $23

When I was living with my dad back in 2007 he was running all the ventilation through the sewer, and we never experienced air coming up through our pipes. This is of course because it was in the basement, I'm sure it would do something if you tried to hook up the exhaust to an upper room. No joke it was the ghettoist exhaust system you could ever imagine, but it had fairly amazing results. So ghetto my dad didn't feel buying a legit fan was necessary so he just cut up a 30 gallon garbage can and modified a 14 inch house fan to fit inside. It's a good temporary solution, but its not something you want to be sticking with for along time because I'd imagine they can smell it in the sewer. If your in the country with a septic let it ride.

Haha nice, how long does a house fan last like that Mole?

I'm not running any kind of op or anything, this is all personal for legal treatment so the smell isn't epic. I just want to keep it out of the upstairs and draw fresh air into the basement at the same time. For small time venting, I'm confident it would not be noticed in the sewers.

there are Several issues with this
one there is a water trap involved.
Removal of this traap can cause some bad stuff to enter your room. Starting with explosive gas. and some foul smells. and Rats and other Vermin.

deflator said:

I'm sure this has been tried, it's just too good of an idea.

Basement growers, why not hook a fan up to a stack cleanout or a floor drain to vent all that smelly air into the sewers?

You would need a way to prevent backflow of course, something like a p trap, but other than that it seems like a good idea. It would be hard to overpower the scent of sewage.

Thoughts? Drawbacks?

Click to expand...

why dont you just buy activated carbon for your filter and refill it, its cheap if you buy it 5 or 10 kilos a time on ebay. if you want to vent in to the sewer its ok except, it might come out the roof stack only if it was a gas and lighter than air or warm air, the sewers are freezing so any warm air wont stay warm for long, when we put the new sewers in the new pipes are tested only to be airtight between manholes for water leakage, it is an absolute impossibility to get any sort of airlock as manholes have cleaning channels, the sewers run for miles, but if everybody did this there would be some amount of smell drifting over the rooftops from all the stacks trying to push up the forced in air, you would have to run your fan constantly to stop methane entering your grow room or use a spring loaded non return door, (methane will kill you and your plants and it has no smell and takes no prisoners) honestly the grass grower is a clever chap he designed these filters to be discreet with no odour. best go with a bag of activated carbon refill, i believe 3mm granules are the size your looking for, you will need to tap your filter for a few minutes to vibrate and settle the granules. a 10 inch filter for an 8 inch duct will take roughly 10 litres. and forget the sewers i build new ones, and i work in the old ones, i was cleaning one in edinburgh scotland there was 3 feet of fat on the wall i used a very high pressure jet of water to slice it all up ( this would slice your foot off in a split second we wear kevlar wellington boots) when i sliced a hole in it for the first time about a hundred rats shot out, i was attacking them with the jet of water. so to let you know that is only some of the disgusting stuff thats down there. and dont forget freddy kruger LOL.

Wow...some people have no idea what they're talking about. There's no trap after the house, and if you tie it in with a wye between the point at which it exits the basement and any vents, it won't blow out the vent stacks...it also won't bubble out your toilets or sinks. If the city smells mj in the sewer, then you live in a city where everyone's shit must smell like weed. Another thing....duct fans aren't worth a shit at static pressure...get a centrifugal inline exhaust fan