Plumbing Oder Question?

[blueridge]

I Have a Sewer smell when weather gets to 32 degrees in the drains in Kitchen and sink drain in half
bath near kitchen, I have cleaned traps under both sinks. no help. washer dishwasher and kitchen and
half bath all drain into a 4 in Plastic and goes about 35 Ft. and Y's into 4 inch from big bath and on
to Septic, there is a 1/2 inch Vent pipe comes from under kitchen sink and through the roof, It's not
plugged, put nose over it. 4 inch seems clean, i think washer and dishwasher would keep it clean?
There is no smell at all in the big bath. Have never had any plugged lines in 35 years, but noticed
oder some lst year. Dishwasher hose does not smell. I'm Thinking of moving vent or adding another to 4
in. would that help. Thanks for any help or ideas Gene

 

[Janicholson]

Traps can get sucked near dry if the vent T is too far from the trap. Is the 1/2 inch a typo? Jim

 

[DoubleO7]

One 1/2 inch vent for all that?

Is it pipe or hose/tubing with maybe a coil or a self made trap somewhere like in the attic?
Might be enough condensation accumulation to create a frozen spot in the vent?

How do you know it is not plugged? If blocked, your not gonna get a whiff of sewer.

Could be plugged with some mud dauber type stuff or bugs or dirt.

If the vent is restricted or undersize, will the flush action of the main bath toilet be enough to vacuum the traps empty??

This post was edited by DoubleO7 on 10/25/2022 at 01:26 pm.

 

[Charles in Aus.]

The obvious questions , how full is the septic tank ? Is the outfall clear ?
It could be generating enough gas to overwhelm the small vent .
Mixing a few kilograms of brown sugar with five or six packets of yeast added to the tank will make the tank work efficiently and smell a little better.

 

[560Dennis]

Your vent stack far enough above the roof ? Is li blocked with bird nest or squirrel
Got a lot or trees block the air flow to draw
You using anti bacteria soap. Dont want to kill the good bacteria , that sulfur smell is from low bacteria activity.
Put table spoon of baking soda in drain to tank get water neutral ph ,bacteria in tank need neutral water ph to thrive ,
We use arm and hammer washing soda with our wash .
Did you have city water or well ?
Some of the things id think of .

 

[showcrop]

There is always going to be smell from a septic tank regardless of how full the tank is. Proper venting is what keeps the smell out of the house. Vents needs to be adequately sized, and not too far from any given drain. I believe that the max allowable horizontal distance from a drain to the vertical vent is 5 feet. If it is more than that a "back vent" needs to be installed higher than the sink. Usually it is put in the wall, but sometimes in the attic. Lack of venting will cause a specific sink to drain slowly, followed by a "burp" when the trap finally empties. As Janicholson stated the water in a trap can be sucked out if venting is inadequate. It usually happens when the toilet is flushed. Vents that go up through the roof can be 1 and a half inch but they need to be increased to four inch within two feet of the roof, otherwise frost can build up and plug them. Vent stacks don't need to be far above the roof surface. I think that the minimum is 18 inches.

 

[tomturkey]

The traps beneath your sinks and incorporated into the water closet(toilet) are there to stop sewer gas from coming into your home. For those traps to work as they should a vent line should be of the same size as the drain line or bigger and exit to the atmosphere. When you smell sewer gas, turn on a faucet very slowly and let it run into the sink for a couple of minutes. That will refill an empty trap and stop the gas. Check out you tube videos and some diy plumbing books to come to a much better understanding of the DWV drain waste and vent system. It is not just an annoyance, sewer gas can kill so take action sooner than later. jmho gobble

 

[Stephen Newell]

I think a 1/2 vent is enough for sink drains. If there is a toilet in the system then it may not be enough. A too small vent would really show up in a toilet. Almost all the water would drain out when you flush it.

An easy way to tell if the vent is the issue would be to put a one way vent on the sink drain in conjunction with the 1/2 pipe. More than likely the 4 drain has an obstruction, not enough to make the water back up but to slow it down.

 

[Mike(NEOhio)]

You mentioned 1/2 inch vent and 32 degrees. One reason vents are 3 inch is so they will not frost up in cold weather. Something I heard a long time ago.

 

[showcrop]

1/2 inch is a typo. The OP intended one and a half inch which is to code except through the roof due to frost.

 

[blueridge]

My Mistake it is a 1 and 1/2 inch vent through the roof, Gene

 

[Janicholson]

That size is Ok for grey water drains like tubs, showers, and sinks. They can be through the roof directly, or T-eed into a 3 or 4 inch Vent through the roof. If the vent is too far from the P trap at a drain location, the flow of water can siphon out the residual water in the trap.
Endoscopes that plug directly into a smart phone (with 5 meter leads) are less than $40 on line. they can be used down pipes and in walls to see stoppages. Jim

 

[Mule Meat]

Could be coming from the washer drain if you do not have a trap between the drain and septic tank.

Try covering it with a plastic bag and a rubber band. If the smell goes away. You have found the source. I have saw them actually inflate a bag some with the right conditions. Can you snake the roof vent? Just cause it looks clear. Does not mean it is.

 

[guido]

blueridge,

1/2 in. Vent? Someone ran out of pipe I guess. I don't know what size drain pipe on your sink, but I think your vent pipe is undersized,

Guido.

 

[Geo-TH,In]

Daughter complained of a sewer smell in her kitchen.

She didn't realize she had to clean the screen in her dishwasher. The dishwasher didn't have a built in disposer..