sewer smell in rv

[putzinaround]

We have been traveling south with our 40' Newmar Mt. Aire for 5 years. This is the first year we have experienced a sewer smell inside the RV when the air conditioners are on. First thing we check is the gas stove, but that isn't it. My husband usually connects the sewer hose, but closes the drain on the sewer and gray water and only dumps when needed. We have done this for years without a problem. We have dumped water down the stool and drains, but hasn't helped. Also, have added some liquid smell deterent, but it doesn't help. Any idea what is going on? When the air goes off, it's gone. Why now and not before?

[Ro646a]

Our former Newmar motor home had a felt like material on the floor of the fresh water tank bay. Water would condense on the outside of the tank and wet the felt material causing mildew odor.

[Robt65]

I also had a really putrid smell coming from mid coach and it turned out to be a house battery that had overheated a cell and I was sure it was a dead cat or varmint of some kind that crawled into the coach and died. Replaced House batteries and no more smell.

robt65

[RVER]

No P trap in my toilet and the pedal stuck in up position and I hooked up to the water at campsite and flood in Bathroom and living room and then out the stairs. SO NO Ptrap in my toilet that someone described as an overflow valve. NOT!!

[Goldencrazy]

I assume you have looked underneath and there are no drips revealing a leak. In my 2016 winnebago the washer was plumbed to black tank. The entry to tank was low-too low- and it would backup leaking a bit where the hose went into the drain. Once i figured out problem-smell-the fix was easy. Never do laundry without black tank valve open. A long shot but you might open areas where a tank or pipe could leak and let your nose guide you. For me small back flow just soaked. Took a major for me to discover and then a lot of gloves, paper towel and bleach. Traded for a DP.

[mtofell1]

Tinstar wrote:

mtofell1 wrote:

Tinstar wrote:
Most RV toilets have a P trap in them

Huh? Every RV toilet I've ever seen drops straight into the poo lake. This is why there are flappers that seal after you flush and we use chemicals to reduce the smell. RV sinks and tub/showers have P-traps like homes. Home toilets have P-traps built in. RV toilets? Nope, no trap. At least they don't clog 🙂

I've only had three different RV toilets and seen a few dozen. They all had a P trap. Granted, it's only a small plastic tube and is there as a safety overflow in case the toilet is slowly leaking water into the bowl. When it gets to the top, the water will overflow through the P trap instead of on your floor. If that plastic pipe gets dried up, the smell has a direct route to the inside of your RV. You might want to look at yours again. I believe you may find yours also has it.

What you're describing is not a P-trap. It sounds like an overflow of some type. A drain/waste trap is a slug of water sitting in a cupped section of pipe to stop the smell of sewer from getting into an area. RV toilets don't have them. Sinks and tub/showers do. For the purposes of this thread what you are talking about could be causing an odor but it's not a trap. RV toilets don't have traps.

[Tinstar]

mtofell1 wrote:

Tinstar wrote:
Most RV toilets have a P trap in them

Huh? Every RV toilet I've ever seen drops straight into the poo lake. This is why there are flappers that seal after you flush and we use chemicals to reduce the smell. RV sinks and tub/showers have P-traps like homes. Home toilets have P-traps built in. RV toilets? Nope, no trap. At least they don't clog 🙂

I've only had three different RV toilets and seen a few dozen. They all had a P trap. Granted, it's only a small plastic tube and is there as a safety overflow in case the toilet is slowly leaking water into the bowl. When it gets to the top, the water will overflow through the P trap instead of on your floor. If that plastic pipe gets dried up, the smell has a direct route to the inside of your RV. You might want to look at yours again. I believe you may find yours also has it.

[Trigger_Happy]

Did you find the problem?

[Bikeboy57]

You might want to take a look at the inside coils on the ac units. They do get wet and can grow all sorts of science experiments.

[mtofell1]

Tinstar wrote:
Most RV toilets have a P trap in them

Huh? Every RV toilet I've ever seen drops straight into the poo lake. This is why there are flappers that seal after you flush and we use chemicals to reduce the smell. RV sinks and tub/showers have P-traps like homes. Home toilets have P-traps built in. RV toilets? Nope, no trap. At least they don't clog 🙂

[RVER]

WE had same and I think it was the trap in kitchen sink was emptying while driving so now we travel with a cloth in the sink drain and it keeps any odors from escaping into rig. Also put a new vent topper on that spins with the wind but do not think that helped much. For us it was the GREY water and not the Black water even though it smells like Black water. Stinks!!

[Executive45]

Most common causes of sewer smell leaks:

1. Bad Air admittance valve
2. No liquid in "P" traps, especially the 'forgotten' P trap for the washer/dryer.
3. Bad battery..in either starter or house battery bank. Use caution as outlined below.

Word of CAUTION.!!! Use gloves and safety goggles if checking your batteries. They can and do explode. Be very careful if one is hot or looks bulging....Dennis

[jplante4]

The AC doesn't put a vacuum in the coach, so I'm not sure that the AC on or off makes a difference. It's probably just moving the air around so you can smell it. Another check would be to close all the windows and doors and turn on a vent fan. This would put a vacuum on the coach and if an AAV or P trap is the problem it will be obvious.

Most RV toilets are a straight shot to the black tank. If your bowl seal is leaking (water doesn't remain in the bowl) then that's another source. Also, you need to let the flush handle snap closed (some types you can lift up for more water) in order to get a good seal. My DW has a thing about making noise in the bathroom and her gentile method of flushing usually results in no water in the bowl and a stink.

[edatlanta]

Are you sure it sewer smell? If you haven't put any chemical in your kitchen gray tank in a while you could be smelling decomposing food particles. This can happen over time if you regularly leave your gray tank open when on full hookups. Small particles build up in the tank and when you then close this tank when moving or boondocking these particles hydrate again and start stinking. Believe me it smells as bad or worse than a smelly black tank.

Been there and done that many years ago. Now I just keep my gray tanks closed all the time just like the black except when they are full and dumping them.

[putzinaround]

Wow, thanks everyone. We haven't tried any of these ideas. I'm hopeful one of them will work.