methane-like smell in basement

Molly, methane gas is odorless, and colorless, so the gas that you are smelling is probably hydrogen sulfide. If so, this sewer gas is coming from a leak in your plumbing vent system, or the water seal in a seldom used drain trap has evaporated. Pour water in all of the floor drains, sinks, and showers that get infrequent use. If the odors persist, then there is probably a leak in the vent system. Call a plumber to check the vent system (a smoke test), and the seals on the sewage pump vault. JWA

Methane has no smell, nor does Carbon Monoxide. I know, I’m a chemist. what you are probably smelling is a mercaptan, an organic sulfide. if its your sewer, its most likely caused by aneorobic germs. That smell, while nasty, is not particular dangerous. Make sure your house trap is well capped, and you can also throw bleach down there, but DO NOT mix with sulfuric acid, a common drain cleaner because you’d be making a fairly strong explosive. SO be safe, and good luck

[Edited by Richard on 27 November 2000]

Did you check your “furnace” moisturizer for possible stagnant water in the humidifier?

Using bleach near a combustion system is not the greatest idea if your looking for longevity of the heating coils.

To be on the safe side I would suggest having a licensed plumber come over and water jet your sewer/waste lines.

A lot of these smells are from crud build up on piping walls that allow bacteria to grow especially today with low flow fixtures not allowing proper scouring action as designed by fixture unit values.

The water jetter will scrub your piping to a like new condition internally and also giving you back full flow as it scours the piping clean as it flushes away years of deposits.

Using a “Smoke test” is also not required as a peppermint test is just as effective and saves you considerable expense (what the heck do you expect from a ditch digger who has NO CLUE to real plumbing)

The peppermint test is very simple to do requiring no special equipment and is VERY SAFE.

Contact me VIA E mail and ILL explain it if you really want to know how to do it.

IM afraid to tell you on here as John will go out into the bushes spraying everything with peppermint, Lord knows how many fires he may have started trying a SMOKE test using his handy dandy smoke machine or smoke grenade making thick pungent smoke inside peopes homes thinking HE knows SOMETHING about plummmin.

A little bit of knowledge is so dangerous.
Smoking people out is really not a nice thing to do.

Try the water jetting and double check around your furnance.

Good luck