26

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.


22

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 operates. The purpose of a vent is to prevent the P-trap from being siphoned, it is not intended to help water go down the drain any faster - in fact, a properly ...


15

No problem, as long as the vent meets the criteria listed below. Not directly below a door, openable window, or other air intake opening (of this or any other building). Not within 10 feet horizontally of the above mentioned openings, unless it's 3 feet above them. Not less than 10 feet from the property line. Not less than 10 feet above the ground. Not ...


14

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 permitted load wet venting. The vent loading (shown) anyway) is at most 8 DFUs (depending on toilet flush size) and while that could (easily) use 1.5" on that ...


11

You are correct that floor drains do need to be monitored and occasionally the trap refilled with water. So the first thing to check is that your floor drain actually has a trap. The way to do that is to slowly pour water in to the drain. You should notice the water level rise and stay there. If the water disappears quickly then it's likely you don't have a ...


11

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 and tie into the existing stack above the upstairs sink drain when I wanted to add a laundry drain.


10

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 working fine and just started acting up, something is blocking your vent pipe. A common cause is a bird nest or dead animal (i.e. rat or squirrel) that crawled ...


10

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 supposed to put rain into the sewer but this pipe catches such a small amount of rain that nobody cares.


9

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 photos of what I did and the components I used. The first thing to do is come out of the wall with a wall tube (otherwise known as a quarter-bend wall tube). Cut ...


8

Take a straw. Suck up some liquid, and put your finger over the top. Notice how the liquid doesn't fall out the bottom of the straw. That's a vacuum lock, and it is one of the reasons why you need to vent your drains. Poorly vented drains don't drain well, and you'll get clicking and bubbling. Your toilet may fail to clear the payload. So regardless ...


8

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 degree elbows purposes to maintain a vertical angle (see Section 224.0, Vertical Pipe). This is to protect the return bend from accumulating waste and to prevent ...


7

It's not based on number of connections, but instead a computed value known as "drainage fixture units". 2012 International Residential Code SECTION P3004 DETERMINING DRAINAGE FIXTURE UNITS P3004.1 DWV system load. The load on DWV-system piping shall be computed in terms of drainage fixture unit (d.f.u.) values in accordance with Table P3004.1. ...


7

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 and hire out plumbing for some jobs. I would only expect to see the 3-piece 180 turn (which is really 5 pieces) done by a hack - seriously. A good plumber ...


7

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 bottle or milk jug, etc. Fill it up with water, then turn it completely upside down to let the water out. The water splashes out with a glug glug glug. Air has ...


6

This has been an ongoing problem in the bathroom sink we use the most. When I was using conventional solutions (Drano and the like) to unclog it, I just assumed that there was a bunch of hair in the drain. This was a problem every couple of weeks, though, and I hated spending so much money on toxic drain cleaners. A couple of years ago, I happened across a ...


6

I had the exact same problem under my bathroom sink. Here's a picture of how I resolved it. The first elbow off the sink is 1.5" because I couldn't find a 1.25" female-to-female elbow in my local Home Depot. I used a 1.25" sized compression washer in the larger elbow to get the smaller 1.25" elbow to fit snugly. Works great! You should be able to do the same ...


6

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 unknown vent pipe top and listen for the sound of running water. One way to make this process efficient is to have two people talking on cell phones. One person ...


6

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 downstream somewhere.


5

I attached 12" plus or minus of electrical copper wire to my drain plug. Copper kills the bacteria. I have not had a problem since, and it has been 4 years.


5

Cutting it off is a bad idea. Aborting the "process of buying" that you're in might be worth considering if it bothers you that much. Relocating it significantly would probably require significantly relocating the septic system, which is very expensive - so you might consider it a "deal-breaker." As for the location in the center of the yard, simply change ...


5

Your system is almost certainly vented. Plumbing vents provide a path for sewer gases to escape so they don't bubble up through the P traps into your house under pressure (the sewer gases will expand and exert greater than atmospheric pressure), and the vents also keep water pressure from siphoning your traps dry, which would create an easy natural path for ...


5

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 PVC is not the best in sun, for my area in desert south west I do not know why builders use it but they do. But same issue occurs on solar water heating systems ...


4

Two options. Air is going in, or air is coming out. "Gurgle" is caused by air being forced through the water in a fixture's trap. It's similar to the "glug" generated when you pour milk quickly from the milk jug. It's air being forced through liquid, in an attempt to equalize pressures. Air in Vents placed strategically throughout the ...


4

Foul odors are usually due to the water seal in the P-trap failing for some reason. Sometimes the water simply evaporates in little used fixtures. Probably not the case here. The other cause for failure is the lack of proper venting. Without a proper vent, the water seal gets siphoned out of the P-trap after the fixture is used. If you have an air ...


4

Other codes may vary, but according to the 2012 International Residential and International Plumbing Code: P3103.5 Location of vent terminal. An open vent terminal from a drainage system shall not be located less than 4 feet (1219 mm) directly beneath any door, openable window, or other air intake opening of the building or of an adjacent building, ...


4

Or, don't vent externally at all. In many jurisdictions you have the option of an AAV - Air Admittance Valve, readily installed in a wall box behind the washer. An AAV involves a gravity seal that opens just when needed to let fresh air into the plumbing pipe. Just makes sure what you get is a real AAV, not just a cheap $3 check valve. They're different. ...


4

1/4" per foot of slope is generally considered the minimum slope, so as long as you have a bit over 7" to work with vertically, you should be able to slope the drain over 30' just fine. You'd set up your discharge p-trap, and then vent immediately after that...tying that back to the main vent stack. So you'll end up with two 30' feet runs of pipe (drain + ...


4

Depending on the size and age of your home, and the location of the plumbing fixtures. It's entirely possible that there's only a single vent stack. If all the drains are within a certain distance of the stack, no additional vent pipes may be required. According to Wikipedia's article on Drain-waste-vent system. ...Under many older building codes, a ...


4

The combo tee has a longer sweep. Long sweeps are easier to run a snake through and drain better as the water path is gradually changed (if you have the space to use them). 45 wye Combination wye & 1/8


4

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 comments) will cause an overflow issue.


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