Black Tank Ordor Solution

All this logic is based on the thought that running the ceiling vent fans is creating negative pressure in the coach and that suction is pulling air out of the holding tanks...

gbopp wrote:

Air Admittance Valve, they come in different colors and styles.

Thanks for the proper description. Was on my phone and just replying was about all I could do. But now at home let me contribute a pic. There are many styles but this black one looks like what I've found in a couple RV's.
Also, some toilets, at least Thetford's, have a vent that bypasses the blade valve. These allow odor into the coach even if there's water in the bowl. Thetford now recommends plugging them.

Is the toilet maintaining a small pool of water in the bottom of the bowl after flushing? If the water is draining out after sitting for awhile, there's a leak around the flush valve seal that can allow odors back into the RV.

j-d wrote:
Check under bath vanity and kitchen sink for drain vents. They have a little cap with a flapper that can rot away and let odor out.

Air Admittance Valve, they come in different colors and styles.

Check under bath vanity and kitchen sink for drain vents. They have a little cap with a flapper that can rot away and let odor out.

Thanks everyone for the answers. I guess I did not word my question correctly.

We were on a shake down cruise and at a campground at Lake Powell. Before heading to Las Vegas for a night and then home, I drained the tanks, black tank first, very strong odor both inside and outside the RV, entry door open, windows open. With a slight breeze blowing and several windows open and the entry door opened and screen door shut, odor cleared in a few minutes. No odor from the grey water tank when drained.

Later, at home, I ran Fantastic Vent fan with all windows and the entry door closed. When I returned after lunch there was a very strong blank tank odor inside only. Fan could have caused a vacuum, but where could the odor enter the RV?

Once again at home I had the fans on and had to go inside the house, with 2 windows open there was once again a strong order inside RV, no odor outside RV.

It is my understanding that the vent system is a closed system inside the RV with the actual vent termination being outside through the roof.

So how would the very strong odor enter the RV? I checked the vent checks and they look new without any indication or backflow from tank, I assumed last night they were working.

I understand that if the tank is not clean and there is a pyramid of poop on the bottom, excessive paper hanging on sensors or any other problem caused by lack of good maintenance of the interior of tank, that there will be an odor from the vents. The vents terminate outside the RV not inside the RV.

In our previous RV, purchased in 1998, and driven to every continental state in the USA and all but three Canadian provinces without this problem ever occurring inside, that there are two problems, poor cleanness and an opening in the vent system someplace inside the RV. Lack of cleanness alone should not allow the system to vent inside the RV, unless there is a failure or damage to the vent system.

If these are not correct assumptions, please let me know what else could cause the problem, by the way, there was a water seal in the toilet and as far as I know, in the shower and the two sinks as they had been used lately.

Next time, before using black tank (after dumping and flushing), put a few gallons of water in there. Will be less smell and solids will flow out easily.

D.E.Bishop wrote:
I have used all fixtures, we did take a shake down cruise and drained and flushed the tanks but I didn't use the wand to see if there was a pyramid of poop there. The smell was so bad all I did was drain, back flush a little and drain again. I'll use the Tornado and the wand and see if we get more solids out. With the water restrictions we have and all it can be very expensive.

I did find a dealer across the street where we bought our tile and wood flooring just 7 miles away. Nexr week.

Every " Gone Southwind " has the same issue, neglect. Got a friend who's new to him SW, 26 years or somewhere around that age has nothing but repair bills. Should of bought a Hauler.

I have used all fixtures, we did take a shake down cruise and drained and flushed the tanks but I didn't use the wand to see if there was a pyramid of poop there. The smell was so bad all I did was drain, back flush a little and drain again. I'll use the Tornado and the wand and see if we get more solids out. With the water restrictions we have and all it can be very expensive.

I did find a dealer across the street where we bought our tile and wood flooring just 7 miles away. Nexr week.

Buy some Happy Camper Super Clean powder online, use it. You will never smell it again. Worth every penny.

Just a thought since you just bought this rig.... Make sure the sinks shower./bathtub drains have water in the P-traps....

When our bathtub goes dry from non use we get a grey water sewer smell....