Sewer gas smell in my basement and house?

I have a very strong sewer smell in my basement and house. We just moved into a house built in 1875. The drains in the basement lead to a septic tank. When we first moved in, the drains continually backed up. Last week, we had a plumber dig up a line and replace a bad stretch of PVC. He also added a trap (it didn't have one before). So we still have one drain without a trap. Since the plumber fixed the line, we haven't had any more backups, but the smell is absolutely horrible! Before the 'fix', we never noticed any smell except for when it backed up. Now, it's a constant strong odor. Any ideas? Sugguestions?
Thanks in advance.

2007-10-25T05:51:32Z

Great advice! I poured water into all drains in the basement, and capped any drain without a trap, and the smell is nearly gone. I still need to check the vent, but so far so good. I really appreciate your answers. Thanks.

gabuilder2007-10-24T09:26:43Z

Favorite Answer

Check your vent to make sure it is allowing gas to escape. Could be restricted or blocked. Birds have been known to nest in them.

sensible_man2007-10-24T08:49:27Z

Plug up the drain that does not have a trap. The water that sits in the trap forms a seal to prevent sewer gases from entering the home. Check the drains once a month to assure that the water is still in them and making the seal. Pour water in them at this time.

Anonymous2007-10-24T08:57:27Z

Sounds like the restricted flow kept enough water in the drain to block the gas, but when it was repaired and a trap added, it drains good, and lets the water in the trap run low. Try adding water to the drain every week, then if it don't do it, try every day. Give it some time to aerate the odor, try exhaust fans. Citric vanilla will mask and eliminate the odor also.

T C2007-10-24T08:51:08Z

sewer gas is lighter than air. It probably is being pushed up through the drain that has no trap. It is overpowering now, because the gas is being forced through the straight drain into your house. You can plug up the drain (only if it is no longer used), or you will have to place a trap in it. Normally the gas would escape to the atmosphere through the roof top vent pipes, because, it can't get through the traps.

rratherbeflying2007-10-24T20:05:27Z

this may be "one of those answers"...... but try pouring a pail of water down the the new line with the trap..... water is what "seals" a trap and if the plumber didn't do this, then there is no "seal" to prevent the sewer gases from coming back into your house.

had this problem with my ex-house. because no water ever went down the drain in the garage, the water in the trap would evaporate in about 6 months...... solution? pour water down the garage drain quarterly to keep the water seal intact.

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