What could cause a bad basement smell that goes away while the heat (which uses basement air) is running?
I can offer a couple of explanations. As you mentioned, you don't think it is sewer gasses, but if you have a floor drain that doesn't have a trap primer on it then I suspect that is your culprit. When a drain hasn't been used in a while then then the water in it evaporates and lets sewer gasses in (sewer gas can smell different than rotten eggs). A little vegetable oil (won't harm the environment) in the drain every three months should do the trick. If there are any other drains in your basement that aren't being used then have a look at them as well. (I know you mentioned it but I always include it in there). The next time your A/C is serviced have your tech take a look at the condensate lines (there should be two: one for regular usage and one for overflow). When your heat is being used the make up air is coming from the basement space and is being vented outside by the exhaust flue. Especially if you have a flue that has an inducer fan (meaning that it has a blower that moves the exhaust gasses).That means that the air is actually being moved outside the of the dwelling. If you have a sump pump, check the "sump well" for anything that could be causing the smell ( I have seen some real nightmares in those places). To check your vent stack just run the water hose in it for about five min if water comes out of it then you have a clog in the vent and will have to be taken out possibly by professional means. I don't know what you mean my 'dehum' but if it is from a dehumidifer then don't put them down a drain for awhile and see what happens. Some alternatives to vegetable oil is R/V anti-freeze or evatorative cooler additive, None of these will evaporate and should only tended every three months. Hope these sugustions help.
How long does it take the smell of weed to get out of a basement?
if your basement absolutely reeks of weed you might be in some real trouble, it's a really strong smell and lingers for a long time. You can cover it up, but try to cover it up with a smell that's kind of natural, whoever you're afraid of getting caught by will think something's suspicious if there's a whole bunch of Lysol in the air.
Why does my basement smell like cat pee?
Sounds like you are having a mold problem... you would be better off replacing the carpet in the problem area. According to the US Center for Disease Control, any carpet that did not completely dry is less than 48 hours should be removed and disposed off as there is the potential from mold growth. Mold is a fetid fungus and some species do have a smell that may resemble rotten garbage, cat pee or sewage. You can also smell it long before you see mold spots. I would also recommend you buy a hygrometer and monitor the moisture levels in your basement or a regular basis. Of you get readings at or above 60% , run a dehumidifier to bring it down. As long as you keep the RH around 50%, you will not have to worry about mold again.
Why does my laundry room smell like a sewer? What can be done to get the smell out?
I’m a master plumber as well as a builder and do phone consults each week for people that have sewer gas problems. Check out this photo and see if you understand what’s going on:The three most common sewer gas issues in laundry rooms are:dried-out floor drain or laundry sink drain (rare cause)new washing machine drain hose inserted in drain stand pipe (quite common)dirty washing machine growing mold and mildew (very common with HE machines)I took that photo above. It shows the common rough-in piping for a washing machine.After the drywall is installed, all you see is the white box in the upper left.Modern washing machines come now with a smaller flexible drain hose attached to the machines. Idiot installers insert the ENTIRE hose into the box above.If you make this mistake, you force the end of the hose PAST the U-shaped p-trap you see under the vertical stand pipe.Sewer gas will come back THROUGH the drain hose into the washing machine if the end of the hose is above the water line on the far side of the p-trap.You should only have about 1 foot of drain hose go down into the pipe that’s extends out the bottom of the box.Mildew and mold growing around / under the gaskets in HE washing machines also cause a sewer-gas-like odor. When the mold and mildew eject spores into the room air, the gas used to launch the spores has a foul odor. When millions of spores launch, you can imagine the stench.I find the best thing to clean mold and mildew is non-toxic oxygen bleach. Stain Solver is one brand, but there are many others out there.If you still have problems with sewer gas after checking the drains and hose length, arrange to have me call you on the phone.Just go to my Homepage - Ask the Builder website and use the Ask Tim page.Want more plumbing #HACKS? SUBSCRIBE to my FREE Newsletter.
In a stinky basement, what is the smell difference between dampness or sewer gas?
There's one smell that you can probably obtain fairly easily that smells almost exactly like the smell of sewer - the smell of the stuff that comes out from between people's teeth when they floss. So go floss your teeth and smell the string. If the basement smells like that, there's sewage getting in, or a drain that has dried out - probably not the one you poured water into, unless the trap leaks or there isn't one. You can tell if it's not holding water in the loop and thereby letting smells come up from the sewer by placing a thin layer of toilet paper over the grille. If it lifts upward when you turn on the A/C, or open/close a door suddenly, then that's the source of the smell. If it's not an open drain or vent problem, then that dampness might be from a sewer line leak, or a leach field (even an abandoned one will smell for decades, and if it coincides with heavy rain or lawn watering, etc., then it could be washing the stuff up against the outside of the basement walls/foundation.