Community Forums

chefred112 · 12-30-2020, 06:56 PM

Every so often i can smell the sewage in the coach..it can get quite strong sometimes. The black tank is on 1/4 full at this time. Took the family on a drive today and about 10 minutes in I can start to smell the sewage (more stronger when i open the bathroom door). It seems to come and go...any ideas what or where it could be?

Ljwt330 · 12-30-2020, 07:04 PM

Quote:

Originally Posted by chefred112

Every so often i can smell the sewage in the coach..it can get quite strong sometimes. The black tank is on 1/4 full at this time. Took the family on a drive today and about 10 minutes in I can start to smell the sewage (more stronger when i open the bathroom door). It seems to come and go...any ideas what or where it could be?

Grey tanks can smell just as foul, so it may be from an air admittance valve located under one of the sinks. Common failures and easy fix. Do you have a vanity in the bathroom?

If the smell is definitely from the black tank, it may be from the vacuum breaker for the tank flush system. They are usually in a wall and hard to access.

It also may be from a bad toilet seal.

Driving with a window or vent open can pull the odors into the cabin.

Breezy2006 · 12-30-2020, 08:08 PM

Agree with Ljwt. Replace the vanity vacuum breaker. Search this group for postings on the replacement, it should be accessible.

If it only happens while driving with windows open and then flushing consider shutting windows for the deed and turning on dash vent or opening the kitchen fan to help equalize pressure.

Mile Marker 42 · 12-30-2020, 08:21 PM

Quote:

Originally Posted by chefred112

Every so often i can smell the sewage in the coach..it can get quite strong sometimes. The black tank is on 1/4 full at this time. Took the family on a drive today and about 10 minutes in I can start to smell the sewage (more stronger when i open the bathroom door). It seems to come and go...any ideas what or where it could be?

Got a washer/dryer in your rig? if you haven't used it in a while, then the P trap is empty and gas is coming right up into your coach. Pour water down the p trap and that will fix it.

Mile Marker 42 · 12-30-2020, 08:23 PM

Quote:

Originally Posted by Breezy2006

Agree with Ljwt. Replace the vanity vacuum breaker. Search this group for postings on the replacement, it should be accessible.

If it only happens while driving with windows open and then flushing consider shutting windows for the deed and turning on dash vent or opening the kitchen fan to help equalize pressure.

Shouldn't have to do any of this, unless he has a vent issue.

twogypsies · 12-30-2020, 10:07 PM

Do you have the bathroom ceiling vent open? Exhaust fan on? These conditions could draw in smells while driving. Sometimes when on curvy roads the toilet's holding water is swished out and the tank smell comes in. Is your toilet holding water?

azSkier · 12-31-2020, 07:28 AM

The seal between the toilet and the floor has aged out and needs to be replaced.

David 70 · 12-31-2020, 09:16 AM

First may sure to keep some water in the toilet. This happens on mine occasionally. Also in the shower drain. I do not use the shower so I try to keep RV antifreeze in the drain as it will not evaporate.

Old-Biscuit · 12-31-2020, 10:35 AM

Quote:

Originally Posted by chefred112

Every so often i can smell the sewage in the coach..it can get quite strong sometimes. The black tank is on 1/4 full at this time. Took the family on a drive today and about 10 minutes in I can start to smell the sewage (more stronger when i open the bathroom door). It seems to come and go...any ideas what or where it could be?

Bathroom cabinet:
Air Admittance Valve on sink drain line
Black Tank Flush Anti Siphon Vacuum Breaker

Toilet Bowl...holds water....bowl seal
Toilet Floor Flange

Sink/Shower 'P' Traps....dry?

LWBAZ · 12-31-2020, 02:52 PM

As one respondent already noted, gray tank odor can be just as nasty as black tank odor. We’ve had the problem you described with two different coaches and the solution turned out to be the same in both cases.

We normally travel with our holding tanks relatively empty, but we also do a fair amount of dry camping at race tracks and elsewhere. In those cases, we often end up leaving & traveling with our holding tanks closer to full.

Over time, we noticed a correlation between traveling with the holding tanks half-full or more and bad odor emanating from the single bathroom in our 2010 Tiffin Allegro Bus and the half-bath in our 2018 Entegra Cornerstone. What those two bathrooms have in common is that they both have a sink and in both cases the sink is positioned directly above the gray tank.

After some experimentation, we figured out that when traveling with the gray tank half full or higher, especially in areas with significant curves, bumps in the road, and/or elevation changes, the waste water sloshing around in the gray tank would suck the water out of the p-trap under the sink. Once that happens you have an open airway between the gray tank and the bathroom, and the gray tank odor will pervade the bathroom and spread from there to the rest of the coach.

The solution turned out to be very simple. Plug the sink and fill it about half full of water before hitting the road. Of course we often forget to do that until we’re underway and start noticing bad odor. But once that happens, plugging the sink and running some water into it will stop the odor from coming in and what’s already there will dissipate fairly quickly, especially with some help from a good air deodorant like Ozium Air Sanitizer.

chefred112 · 01-01-2021, 08:30 AM

Thanks all for all the great info! I'm reading an re-readung the posts to process all the info provided. Am planning to take a drive in her today and will try the sink tip. I want to add water into the system and try and dump what little I have in the grey/black tanks...mind you, this is my 1st ever rv, only have done #1's to test out the system. Have never been to a dump station before. Haven been watching vids on the dump process, also looking at the water panel to see how the process works with what I have.

chefred112 · 01-01-2021, 08:40 AM

Pic of water panel

Brentw · 01-01-2021, 08:48 AM

Although this was on an older unit, my BIL chased down his odour to a disconnected vent cap. Don't know wether it was from new or a repair, but the vent stack was open to the attic area.