How Can I Vent Through The Sewer?

SmokeyMacPot

SmokeyMacPot

New Member
A common alternative to venting up the chimney is venting into the sewer pipe. Depending on how your house is built, if you push air into your sewer pipe, the air may travel up through your house sewer standpipe. However, it is possible to vent directly into the actual sewer system.

Venting into the sewer is generally safe. If someone is working in the sewer nearby, they might smell the sweet pungent aroma of your crop (Not likely at night), but they have no way to tell where on the block it is coming from. Since the pipes large enough to walk in are quite far away from individual homes, the smell has lots of time to dilute.

[Editor’s note: the stinky sewer will also hide your crop's odor up to a point. The sewer system itself is sealed, but you should check nearby manholes covers just incase for excessive blower noise and smell. The undeground sewer system will also remove and cool exhaust heat - excellent protection against infrared detection.]


To start you will need to locate your sewer pipe in your basement. This is the pipe coming from your toilet(s) on upper floors.

Near the basement floor, there should be a “Y” connection at an angle, with a cap on it. Some houses have metal pipes, other houses will have ABS or PVC plastic sewer pipes.


You will need a pipe wrench to remove the cap. Sometimes, if the house is very old, you will need to demolish the cap to get it off. You can buy a new one later at the hardware store if you need to.
This will reveal a hole 3 or 4 inches in diameter, depending on where you live, it may even be another size.

CAUTION: Fumes from the sewer can be poisonous, so make sure to use caution when removing the cap, and once a fan is installed, make sure to keep it ON all the time , so that there is no backflow into the home.

You will need to visit a hardware store, and pickup the various connectors and aluminum flex ducting to connect a fan to the hole. The most efficient fans for this purpose are centrifugal inline fans, but a squirrel cage fan will work too. The major difference is power consumption - an inline fan will use about 1/4 the electricity of the same size squirrel cage, they are VERY efficient, but a little bit noisier.


The fan here is 438 cfm, and only uses 115 watts. The inlet and outlet ports are 6 inches in diameter. I use a reducer from 6" to 4", and then I use 4" aluminum dryer ducting to the sewer hole, and of course plenty o' duct tape!

Once you are finished, you can test your work by standing outside the basement door, and holding a lighter to the crack at the bottom of the closed door. The flame should shoot inwards, because air is being drawn from the upstairs.

If you have successfully create this 'negative pressure' environment, there is no way that odorous grow room air can enter the house, hence the smell is contained!

[Editor’s note: the sewer contains methane – a smelly and potentially explosive gas! Keep those gases away from your water heater pilot light!]

Author: JonJaffer
 
:geek: Perhaps plug the fan into a Uninterrupted Power Supply to keep the basement from filling with sewer gas in the event of a power outage (especially if there is a gas heater or water heater located in the basement.) :rocker: :smokin:

:rollit:
 
I recently read an article in the paper that the goverment was going to put money into stopping people from dumping into sewer lines. Supposidly they said they had a way to find what house have a pipe rigged up to the sewer thats not suposed to be there.. again this is for people illegally dumping but i would be carefull.......

i do have related question... once the air is filtered by the carbon filter and leaves out the chiminey... is there any smell after going through the filter at all????
 
Just the faint smell of activated carbon that u could only catch a whiff of if u put ur nose to the edge. even I f ur filter "expired" I would think that molecules would dissipate so there would be no strong aroma by the time it hits ground level. Make sure U mask the light coming out of the chimney. U'll mess around and look like ur callin Batman, but I bet he's not the gonna be the 1 knockin on ur door. But I'm speaking theoretically. Filter + chimney exhaust = :rollit: and the u can go on vacation and :surf:
 
dirtyjerz said:
thanks bay area! good point with the light comming out of the chimney.... seems like an easy precaution to forget about
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Don't thank me, thank our neighbors up north. Many a Cannuck (or so I've read) have had this problem drawing attention to their grows years back it was a common problem. I'm just passin on info. But ur :welcome: :peace:
 
ive been doing plumbing for a long time and all this makes perfect sense, and as far as i can think would work as said.

BUT

what happens in the event your sewer backs up?

I honestly think it would be worth the headache to get the sewers cleaned before the grow just to be safe....
 
I would be careful about venting heat into the sewer discharge pipe. If you have a lot of discharge water going at certain points in the day then I think you would be cool but if its a one man show it could be a different story. The heat would dry out turds and toilet paper thus making a shitty sort of green concrete, or should I say brown, that would stick to the pipe. At some point your flow would be restricted then possibly clogged up to where it would take dynamite to unclog it.
 
If you do end up venting into the sewer.I would suggest some form of odour control. Ozone is a cheap option for external venting like this. It would be a shame to have a house that doesn't smell like ganja ... only to get fingered by a keen nosed sewer sleuth.
 
exAkT said:
ive been doing plumbing for a long time and all this makes perfect sense, and as far as i can think would work as said.

BUT

what happens in the event your sewer backs up?

I honestly think it would be worth the headache to get the sewers cleaned before the grow just to be safe....
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I was growing in my basement and my sewers backed up, to get it fixed I had to call my landlord. Oh sh??, I had to move everything before I could do that, a big hassle. Turns out tree roots grow through the sewer line and it needs to be snaked out about once every two years. So yeah, unless you can move everything quick like for a landlord or plumber I would think about getting it cleaned out first. Awesome advice there:goodjob:
 
Tree roots are a big problem in sewer lines. Running ferts down the sewer drain really makes 'em a problem.

A lot of municipalities run little "smoke" tests to see who's old house has it's gutter and sewer lines running into the storm sewers. The smoke will rise up and out the gutter spouts and vent pipes. That get's you a knock from the city building inspector,who's going to come in to see what the problem is.

If you've got metallic flex conduit running from an odd little room to a fan on the sewer head,he's going to get real suspicious and want some answers 1; Because you built that little room w/o a permit 2; You won't let him look inside,and 3; he knows you're up to something.

He's going to call the cops to come over for assistance and you're going to get busted.
 
Please help!
Im new at this, and want to do it right but I don't understand some things.
I don't want to sound like an Idiot.. but I don't understand if you hook a fan up to a vent and piping to the sewer wouldn't it suck the air/chemicals into the room????? I'm so confused, I understand the whole point that you want to push the air into the vent/pipes and into the sewer... but wouldn't you need a vaccuum type of fan?

thanks..:thankyou:
 
cchun01 said:
Please help!
Im new at this, and want to do it right but I don't understand some things.
I don't want to sound like an Idiot.. but I don't understand if you hook a fan up to a vent and piping to the sewer wouldn't it suck the air/chemicals into the room????? I'm so confused, I understand the whole point that you want to push the air into the vent/pipes and into the sewer... but wouldn't you need a vaccuum type of fan?

thanks..:thankyou:
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hey bud. welcome!!! they are speaking of an inline fan do a google image search for them and youll see the fan can be turned either way, to suck, or blow. as stated above, there very efficent, move a ton of air, but are fairly loud. something to always consider. :Namaste:
 
Question:
When venting to the sewer vents in the bathroom (the fan that you can turn on to get the smell out, that sucks air up and out the house) or I guess any vent that go to the top of your house, what are things you have to worry about?
I noticed in the upper thread it said light.. BUt how could light escape out? And I guess there would be heat going out also since its coming from the grow room, but is that still okay? Is heat coming out of a vent in the top of the house going to be obvious that something fishy is going on?

Sorry for the noob questions guys
Thanks for the help
 
I'm new to this. Trying to figure out the sewer system. As far as I can tell, the drains from toilets, tubs, sinks, showers, and floor drains (everything inside the house) all go down and collect together at the lowest level and out to the municipal sewer. This municipal sewer is a sealed system and so I would suppose they would never vent anywhere in a populated area. The pipes are too small for someone to walk into until they collect into bigger pipes, probably far from your house. This should give lots of time for the really smelly sewer gasses to mask your grow exhaust smell.

One point that was raised at least once, is that your house's sewer pipes have a vent pipe (a "stand" pipe) that goes vertically up inside a wall and eventually through your attic space and through the roof. The purpose of this vent as near as I can figure out, is to prevent an air-lock situation whereby a sudden downward rush of water (and shit and paper) would cause suction, or negative pressure, within your pipes that could potentially siphon out the water from one or more of your traps leaving a path for sewer fumes to come into your house. (please correct me if I'm wrong). I think if you install a valve near the top of this vent that would allow air to come into the vent but not out of the vent then it would still serve its purpose of preventing air lock, while preventing your grow room exhaust from blowing freely out of the vent up on your roof for your neighbors to smell. Any thoughts on this?

About the point about sewage drying on inside your sewer pipes because of the constant warm exhaust air being blown through, I think this is a good point if you have the new low-volume or low-flush toilets. I don't like the thought of sewage being flushed away with a minimal amount of water. Here in Canada water is cheap and although I don't like to be wasteful, I'd rather play it safe. I retro-fitted my toilets with the old full-flush valves so I'm sure all of the sewage makes it all the way out of the house pipes into the sewer with every flush. I think you wouldn't need to worry about anything drying on inside your pipes then. (thoughts?)
 
one more point... about the possibility of sewage backing up into your grow room; If your exhaust is vented at floor level, I agree that if your sewer backs up you could have a problem. In stead, cut the sewer drain pipe (usually a 4" ABS plastic or metal in older buildings) up high near the ceiling and tap downward into the pipe with a Y fitting. In the event of a sewage backup, it would have to fill up that additional 7 or 8 feet of 4" pipe before going into your grow room vent duct.

If you're worried about backflow, you could have an anti-backflow valve installed where the sewer pipe exits the house but that would be expensive. If backflow is a problem you might want to have this done anyway or else it could come up your basement floor drains. If you do have big trees in your yard where the drain goes out to the street, you might want to have the pipes checked before starting construction on your grow room. I had this problem in one house. They had to dig up the front yard and replace a segment of iron pipe where roots from a tree had cracked it and clogged it up with roots.
 
As a Journeyman Master Plumber and 20 year union member, I would say this is goofy. The smell will flow in to the sewer but ultimately back out through ventstacks, either at your house or your neighbors. The smell won't magically vanish. Uh, breaking a trap seal requires a permit. If you think you want to do this, definetly buy a back flow preventer and install it downstream from your fan hook up. Logically though, a fan unfiltered directly to the outside is about the same.

I'm imagining my neighbor with a hole in his yard cleanout cover and the smell pumping onto his front porch. I hope the manhole in the sidewalk in front of his house is artight, or everyone who bikes and walks and drives by will smell it. I think it's possible to create enough back pressure to siphon every trap at my house, so none of my drains will work.

It's actually tough to be a licensed plumber when everyone thinks THEY are a plumber. In general, I would also say that stoned people rarely write coherent articles. This is a classic.
 
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