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26 votes
Accepted

What is this tube sticking out of my roof?

Almost certainly a vent for plumbing. It connects to the sewer, so it doesn't need a cap. It's highly likely there's a sink or other fixture nearly below it.
Aloysius Defenestrate's user avatar
22 votes

Does my toilet drain poorly because of bad venting?

It's a common misconception, but blocked vents do not cause slow drains. If you Google it, you'll find lots of incorrect information that completely ignore the physical realities of how a vent ...
Nuclear Hoagie's user avatar
14 votes

Does my toilet drain poorly because of bad venting?

Unless something is clogged, this should work fine (assuming appropriate slope on all lines.) The vent should be 2" for a 4" line, and is only draining the tub (2DFUs) which is half the ...
Ecnerwal's user avatar
  • 222k
13 votes
Accepted

Alternative method for connecting sink drain with waste pipe directly under?

Since this is NOT buried in concrete, don't use a glue-together trap at all. Problem the first (apart from what you mention) is that the vent is too close to the trap - it needs to be at least 2 pipe ...
Ecnerwal's user avatar
  • 222k
11 votes

Is my plan for an air admittance valve ok?

The valve needs to be downstream of the trap, basically in the position an actual vent would be. source Also, be sure they're legal where you are. My local inspector forced me to run a new vent line ...
isherwood's user avatar
  • 142k
10 votes

Why does flushing a downstairs toilet cause an upstairs toilet to also flush?

This is a classic venting problem. If it has NEVER worked right, someone designed something wrong and it's going to be expensive to fix now because it will entail opening up the walls. If it WAS ...
JRaef's user avatar
  • 15k
10 votes

What is this tube sticking out of my roof?

It's a vent pipe for the plumbing it connects eventually to the sewer. It will catch a small amount of rain but the rain will stay inside the pipe and eventually reach the sewer. You're probably not ...
Jasen's user avatar
  • 22.1k
9 votes

Sink tailpiece doesn't line up with trap

The photos posted above were really helpful, since many people may not know what connectors and adapters are available -- as I didn't before replacing two vanities. Therefore, I thought I'd post ...
HomeHandyman's user avatar
9 votes

Alternative method for connecting sink drain with waste pipe directly under?

Ended up moving the waste pipe in the basement for a cleaner look. Let me know what you guys think.
Paulz's user avatar
  • 173
9 votes

Is the DWV Tee in this washer service installed backwards?

Yes, it's backwards. That's an air admittance valve at the top, though. That's a vent. Any ol' tee pointing up is fine. Unprofessional but fine. I suppose an inspector could point to IPC 905.2 to say ...
popham's user avatar
  • 10.5k
8 votes
Accepted

Tee vs. wye for drainage?

This is best summarized by referring to building code: Building codes vary, but this seems to be a fairly typical set of rules (at least in the US) such as in the Florida plumbing code. If in doubt, ...
StayOnTarget's user avatar
  • 5,605
8 votes
Accepted

Why are loop (Chicago) vents typically built with three elbows?

From the International Association of Plumbing and Mechanical Officials (IAPMO) "Uniform Codes Spotlight" archive from February 2018: The configuration of the return bend using 45 degree and 90 ...
kponz's user avatar
  • 1,084
8 votes

Why are loop (Chicago) vents typically built with three elbows?

There is no reason you need the three sections vs one 180 degree return piece other than you have copied in one of the oldest and most used plumbing pictures on the internet. I do my own plumbing ...
DMoore's user avatar
  • 49.4k
7 votes
Accepted

How does a plumbing vent work?

Pluming vents do two things - they allow air in and they allow air out. Simple right? The first need of allowing air in can be visualized with a plastic bottle that has a narrow neck, like a soda ...
JPhi1618's user avatar
  • 28k
6 votes

How can I tell if a given roof vent is still active, connected?

One thing you can do regarding the question if it an active part of your plumbing is to turn on your water sources one by one. While water is running down the respective drain put your ear to this ...
Michael Karas's user avatar
  • 65.4k
6 votes

Does my toilet drain poorly because of bad venting?

Run some water in the tub until the problem shows, then get under there and slap that pipe to see if it's full of water it should be mostly empty and sound hollow. If it's full there's a blockage ...
Jasen's user avatar
  • 22.1k
5 votes
Accepted

Can PVC be encased horizontally in concrete

PVC pipe embedded in concrete should be fine under most codes I've seen. You'd need to sleeve something like black, galvanized, or no-hub iron pipe, but PVC and ABS are impervious on any reasonable ...
Joe Makes Things's user avatar
5 votes
Accepted

Is PVC an acceptable pipe for a vent stack through the roof

National (international) plumbing codes identify vent pipe size, length above the roof, flashing and caps. But does not specify material. PVC, ABS and galvanized have all been used. You are right ...
spicetraders's user avatar
  • 1,078
5 votes
Accepted

Can a plumbing vent go up a different drain, for some length

Your concerns are valid: The provided sketch would not pass any plumbing code that I am aware of. It indicates a vent from a separately vented fixture connecting to the drain portion of another ...
pdd's user avatar
  • 6,059
5 votes
Accepted

Is there any filter or material that let only water through not dirt

You can get "drain tile sock" or drain tiles with "sock" installed at just about any place that sells building materials. These are used where you want to allow the water to pass ...
jwh20's user avatar
  • 23.4k
5 votes
Accepted

Should PVC DVW landscape pipe be glued?

I chatted with a friend that is a landscape/garden installer. He strongly recommended gluing each joint to keep roots out of the drain system. His take was that less expensive landscape contractors ...
HikeOnPast's user avatar
5 votes
Accepted

Can a 2" pipe connect vertically to a 3" pipe before it hits the vent?

That arrangement should be fine, provided the shower has an individual vent (see sketch 1). The other option is to connect to the stack above the tee for the toilet with a 3 x 2 tee (see sketch 2). ...
pdd's user avatar
  • 6,059
4 votes

Persistent sewage smell coming from basement drain

My friend had a persistent sewer smell in the basement -- and it became so bad that it permeated the whole house to the point that she couldn't live there. This was in late summer of 2016. She had ...
Jim's user avatar
  • 41
4 votes

How do I eliminate stink from a waste water pipe?

Cut the current pipe and install the p-trap near the bottom, close to however it's vented. Retain the cut piece of pipe and add it back above the new p-trap. Gluing to the top (as mentioned in ...
Tyson's user avatar
  • 4,230
4 votes
Accepted

What's causing the sewer to back into the tub?

It turns out that there was a partial blockage in our drain between the DWV and the main sewer line. Because it was a partial blockage, some water could drain, but when there was a lot of water, and ...
Wayne Werner's user avatar
4 votes

How to stop downstairs toilet from bubbling when upstairs toilet is flushed?

It seems to me that what is happening is when the 3rd floor toilet flushes, the volume of air in the 3 story length drain pipe needs to go somewhere, and it is venting out through the ground floor ...
ArchonOSX's user avatar
  • 20.2k
4 votes
Accepted

What is the correct height of a toilet flange relative to the finished floor?

The original intent of the toilet flange is to screw down to the finished flooring, not below it, definitely not shimmed up above the finish floor, although there is a small bit of room if there is a ...
Jack's user avatar
  • 35.9k
4 votes

What size drain is required for a washing machine?

You're correct, the requirement for washing machine drain is 2". To determine if you have enough drain capacity for an additional machine, you need to consult the Uniform Plumbing Code's Drainage ...
Jeff Wheeler's user avatar
  • 3,382
4 votes
Accepted

Can a sanitary vent take a jog around an obstacle?

The magic number is: 6" above the flood rim of the highest fixture on the floor served by the vent. Unless you have a very strange bathroom, that highest flood rim is probably the sink in the ...
Ecnerwal's user avatar
  • 222k

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