Thread: short, capped DWV vent

On an old 1930's house we stayed at in the Hudson Valley.

Anyone else seen anything like this before?

Added with edit 01 - took these on my cell phone and they opened up right side up on my computer, but not here, so I'm going to have to rotate the photos 90 degrees right and replace them.

Added with edit 02 - rotated the photos 90 degrees to the right and now they are showing up facing to the right??? Will have to try rotating them back.

Added with edit 03 - okay, the photos are showing up vertically now, now sure why this board did what it did, but all is well that ends well.

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Jerry,

I am thinking it is a variation on what is referred to in my area as a "Contra Costa Valve". A newer variation is a "sewer popper". The only thing is that the one in your pics looks to be taller/higher than what I am used to seeing. I don't know what the real name of the valve is. Sorry.

Basically, if there is a sewer main clog, it allows the sewage to spill out onto your yard instead of backing-up into the house. Not sure if that can be considered a real improvement, but required in some areas.

http://www.jonesstephens.com/wp-cont...wer_Popper.pdf
How to Prevent a Sewer Line Backup | Diamond Certified Expert Report

Here are three more photos I just took, showing the inside is designed to be pinch-bolted in place.

Better in the yard, yes, for the occupants ...

It looks pretty much like a typical sewer vent that I see at most houses.Usually located in the front yard or near the curb, but near the house is not uncommon. Don't you see this in Florida?

None in Florida that I've ever seen.

Jerry,

It didn't have a ball in in, I assume. But, it kind of looks like it should have. Those nubs inside the cap might center a ball.

Could it be a fuel tank vent?

Originally Posted by Gunnar Alquist

Jerry,

It didn't have a ball in in, I assume. But, it kind of looks like it should have. Those nubs inside the cap might center a ball.

Gunnar,

The nubs keep it propped up on the rim of the pipe to allow venting.

Originally Posted by Roy Lewis

Could it be a fuel tank vent?

It's next to a bathroom with no other visible vent.

It's cast iron and 4" ... which is likely larger than a fuel oil tank vent, and, I suspect, this commun-it-y ( ) would never have allowed underground fuel oil tanks.

Jerry,

The purpose of the ball in a "Contra Costa Valve" is to keep sewer gases from venting back into the house, but will move out of the way to allow a sewage spill (or prevent a backup into the house - your choice). Since the top is always open at the one you had and it looks to be above the interior floor level, I would say the function is different and just a vent. But, wouldn't the lovely odors go back into the house via the nearby open window?

Originally Posted by Gunnar Alquist

But, wouldn't the lovely odors go back into the house via the nearby open window?

With a system operating as it should, the main purpose of the vent is to let air in (the piping should drain basically dry and the waste should be carried down the pipe, there shouldn't, at least typically is not (from my experience) a lot of odor coming up from the vent (some, but not a lot ... not that I would want to 'huff' the air coming out of the vent).

That said, there is a reason for the clearances required for plumbing vents from building openings ...

I don't notice any odor out of that vent, and there are spider webs in the pipe.

No 'fuel oil' smell either.

Yes, it looks to be slightly above the floor level, so it would not be there for the purpose you describe.

The property is on septic, so it likely would not have a "building trap", but, based on its age, it might have, and maybe that is a vent for a building trap (although I don't recall any building traps having vents?

They are a very common thing in this area. Some have three screws and some have one. Newer ones are plastic.

https://shop.edyoungs.com/products/4...cap-15997.html

Yep, mushroom cap for the stink pipe. That's the technical jargon :-) Often called a "curb vent".

Yard vents allow better flow but also provide convenient access to plung the vent with a pole and rubber plunger made for that purpose to break free clogs. Backed up drains can often be corrected by a few quick jerks on a plunger out in the front yard. Every plumber in Eastern PA I know of carries a 10 foot length of 1/2" NPT pipe threaded onto a 4" plunger with a 3" in the truck.

https://www.youtube.com/watch?v=1U1QwXMvwmQ

some of these have cast iron louvered caps but same deal. You can also run a drain cable down these vents to the street. Just be aware a heavy duty cable can blow through old terra cotta tile sewer pipe joints where they make a bend. Been there done that. Had to dig up street but it was water depts. fault.

Originally Posted by Mark Reinmiller

They are a very common thing in this area. Some have three screws and some have one. Newer ones are plastic.

https://shop.edyoungs.com/products/4...cap-15997.html

I never realized mushrooms needed venting.

Originally Posted by Mark Reinmiller

They are a very common thing in this area. Some have three screws and some have one. Newer ones are plastic.

https://shop.edyoungs.com/products/4...cap-15997.html

Yep, that's it.

Thanks to all, and Bob for the video - still learning new stuff every day.

Jerry, Was there a septic tank at property?

Originally Posted by Tom Rees

Jerry, Was there a septic tank at property?

Yes, there was.

And I could hear water rushing through that vent outside the bathroom whenever water was used in either bathroom or the kitchen (the laundry was also in the kitchen).