Strong odor from sink in motor home

[Maysc]

Anyone notice a strong odor from sink in motor home. At first we thought propane, but it was not.

[TWP723]

Check the P-trap.

[oldmanAZ]

Be sure the P-traps have water.

[Screwby]

Grey tank odor, if your going be to gone for awhile you can pour a small amount of vegetable or olive oil down the drain. Over time the water in the Ptrap will evaporate and allow odor/fumes to come out sink drain. The oil won’t evaporate and helps keep smells at bay.

[RogerR]

Do you have a Studor vent under your sink? My 195rb has one and it failed with a major odor backup there. Very little clearance, and I did not see why it was needed so put a plastic bag over it and zip locked in place, no problem since.

[RetiredLEO]

Some white vinegar and cap it or mix some baking soda water to pour down.

[edatlanta]

Kitchen gray tanks will accumulate small food particles over time and can and will eventually start smelling worse than a rotten black tank. It is a different smell, but as bad or worse in my book. I always keep my kitchen tank closed and only dump when full just like I do with my black tank. A little bit of black tank chemical in the kitchen gray tank solves the odor issue for me.

[RetiredLEO]

A good dose of bleach down the sink works wonders

[ALJO]

Oil down the sink drain is a bad idea (even at home). Cleaners is OK. Poor vinegar down the drain will stay in the trap and doesn't evaporate like water does.

[oldmanAZ]

Originally Posted by ALJO

Oil down the sink drain is a bad idea (even at home). Cleaners is OK. Poor vinegar down the drain will stay in the trap and doesn't evaporate like water does.

Until today, I've never heard anyone say that a teaspoon or tablespoon of vegetable oil in the sink p-trap is a bad idea. Why is it bad?

When we're traveling for any length of time, we use vegetable oil in our sink p-traps in our house without a problem. We don't need to use it in our TT.

[Jagiven]

You do not mention under what conditions the odor arrived.

My shower's P-trap sometimes when we travel the water sloshes out, and we get odor back into the bathroom. I now just keep the drain plug in it, and pour a bit of water down the drain if we notice an odor.

Another thing to check is the vent (AAV) under the sink, it has a spring actuated cap, sometimes these things stick in the open position.

I also do not drain the tank completely anymore. I treat the grey tank a bit like the back tank, and add a few gallons of water back into the tank to keep the good bacteria health.

I never recommend bleach down the tanks, as it will kill all the good bacteria, and then you will have odor.

Only time I purposely pour oil down my drains is in the fall, after I winterize, to keep the antifreeze from evaporating.

Sometimes I will add about 1 cup of water softener or fabric softener to 5 gallons of water and pour it down the drains, and let it soak until the next dumping. The sloshing seams to help wash the tanks and sensors.

[Screwby]

Originally Posted by ALJO

Oil down the sink drain is a bad idea (even at home). Cleaners is OK. Poor vinegar down the drain will stay in the trap and doesn't evaporate like water does.

Grease down a drain is bad, oil is not. Grease will solidify in the pipes slowly decreasing flow and causing clogs. Oil will not hurt anything as it doesn’t solidify, it flow as easily as water through the pipes and out the sewer dump. Plumbers have been giving this advise since I can remember, I’m assuming plumbers know about plumbing. It’s been long advised if your leaving your house for an extended amount of time that pouring a small amount of vegetable, or mineral oil into your Ptrap will keep the drain from drying out and septic smells out of the house. Same school of thought applies to your camper as long as you have Ptrap drains then they can dry out and allow vapors/smells from the holding tank back into the camper.