why do i sometimes smell sewer gas in my home?

Question

i have checked vents on roof they seem clear the smell comes from the airconditioner closet where there is a drain connected to thetwo sinks and awasher drain the smell comesand goes got anyideas also itseems to travel in the return air vent

Answer 1

Heres the deal, There is a trap in your drain for your a/c unit. If you havent been useing the a/c, the trap may have dryed up , allowing sewer gas to come into the a/c unit . Try pouring water into the a/c drain, filling the trap with water will stop the gas smell. Strong winds can also empty drain traps out letting gas in.

Answer 2

It sounds like your trap is dry. There should be a small amount of water in the pipe if there isn't, you are going to have gas coming back into the house. The trap is the curvy pipe under the sink.

If the toilet seal was leaking gas, it would also most likely be leaking water. Check the floor around the toilets for evidence of leakage. If you have a vinyl or linoleum floor, leakage can be hidden for years between the flooring and the subfloor… especially if it is just a slight seepage. (Be mindful that this seepage can also generate odors.)

After you flush the toilet, does the water in the bowl rise at least a few inches above the level of the bowl's drain? This is important because the water in the bowl acts as a "trap" to keep the sewer gas out. It is possible that some gas could escape if the level in the bowl is too low. If you have the tank water level set too low or are using water displacement devices in the tank, such as bottles, bricks or "commercial" products, the amount of water entering the bowl will likewise decrease.

Another possibility is that you are getting downdrafts off the roof and the odorous exhaust from the roof plumbing vent is entering through open windows. Since the windows are probably closed most of the time in the colder months, you wouldn't notice the problem in the winter. Downdrafts are often caused by tall trees too close to the house. Cutting down the trees or increasing the height of the vent "stack" (the vent pipe that exits the roof) might help if you determine this to be the problem.

There is the remote chance that there is a trap missing in the tub/shower. When the seasonal odor appears, tape a plastic bag over the tub/shower drain and see if the odor dissipates. In fact, you can do this to each fixture to try and isolate the source of the odor.

Sounds like a dry trap to me.

Hope this helps and Good luck! (Been there bud!)

Answer 3

I have had that kind of odor in my kitchen right near the sink. So I took 1/2 Cup of vinegar and 1/2 cup of Baking Soda and let it foam up then pour boiling hot water to flush it all out, Then a week later I bought Draino, and used it in all the sinks in the house,So Far So Good. Maybe there was a build up of something in the drains.
No more odors.

Answer 4

Does this smell coincide with when you run your washing machine? I have the same problem, but my washing machine drain is not vented properly. When the cycle spins out the water, the smell permeates my downstairs bathroom and bedroom. I've learned to keep my downstairs bathroom door shut till I can come up with the $2000 to have a plumber properly vent it. Good luck.

Answer 5

A plumber friend of mine told me to pour a pail of water with some baking soda added to it down your basement drain once every couple of week. I did and I never had sewer gas smell.

Answer 6

if your house is not slab then it could be you have a leek under your house. turn water off to house and add about a gallon of bleach to each drain. then wait for a while and see if the smell gets better if not you may want to call someone to look at it. if you have a water leak it can get bad quick, but if it is a sewer leak then it can be worse. call someone who will go down and check it out. also you may want to go look with them.

Answer 7

if there is a S pipe in the sink that it drains into and it isn't used much it may be dry. just pour water into it and see if the smell goes away.................all S pipe/ traps have to have water in them to keep out the sewer gas smell

Answer 8

I would get a plumber I could trust and pay him to give you an opinion because that might be a backup in the drains or an old septic tank.

Answer 9

I would think it is coming from your sewer drain. Usually located in the basement.

Something has backed up in your sewer. We had this problem and they had to dig a big hole in the ground to remove the blockage.

.

Answer 10

GOT A SEPTIC TANK?

CHECK SEE IF IT NEEDS EMPTYING>>>>>IF NOT IN LAST TEN YEARS ECT-PROB DOES...

CHECK VENT STACK PIPE ON TOP HOUSE..MAY BE CLOGGED WITH LEAVES/TRASH/BIRD NEST - STICK IN GARDEN HOSE AND TURN ON WIDE OPEN,, FLUSH.

LOT OF TIMES WHEN THIS HOSE IS RUNNING WIDE OPEN
WATER WILL SEEP FROM AROUND SEPTIC TANK LID--YOU KNOW FOR SURE ITS FULL THEM....