Help with bathroom odors

[mcurcio1989]

I have converted a century class freightliner into a toterhome. It was a a 7 month project and I started basically from scratch about a year ago. Everything is working pretty good but the bathroom area.

Here is the problem. The bathroom had been installed and was working good for a couple weeks and after taking the rig to a weekend concert event, with 10 friends staying in it mind you (it has a U shaped loft / storage bunk area that can sleep about 6 people, in addition to the 2 fold out couches and dinnette conversion bed), It developed a smell it is an odd smell it is almost soapy with a hint of sanitation smell.

The bathroom is very compact due to size limitations so it is a basically a combination toilet area and shower. I formed the base of the shower and gave a generous coating of redguard to seal it and then tiled it in.The walls are all FRP which has been caulked in. Basically the area is airtight. You cannot smell anything from the area with the door shut. I used a 12 volt boat engine compartment blower for ventilation and that thing can change the air in the room in seconds. The plumbing is all pretty custom. I built the tank myself and it is a rectangular box built from 3/4" plywood with the interior generously coated in epoxy resin fiberglass. It has a division in the middle that is sloped so the black is on top and can drain and the grey is on the bottom. The tank sits directly below the bathroom and due to space limitations I had to get tricky with the plumbing. The piping for the shower drain is actually inside of the black tank. So it is PVC with a catch that than drains into the grey tank through a combination vent using a Y inside of the black tank. The toilet plumbing goes straight in like normal. The sink drain runs in through the blacks vent and then then the grey and black vent merge together and then one pipe runs up through the roof.

I tried removing the toilet and plugging the hole using one of those rubber plugs from HD. That effectively plugs it and verifies to me that this smell is not a leaking toilet seal. It is a different kind of smell. We then throughly cleaned out all of the bathroom, leaving the toilet removed and plugged and tried to see if the smell would stay gone but it came back. I am really confused as to what is causing this smell. It seems to be strongest around the shower drain but I do not know why. It is rendering the bathroom unusable Part of me wonders if it just has to do with the fact that it is a small humid area with almost no air movement so the air is just kind of going stagnant but it seems to be more than that.

I would really appreciate and ideas and advice you all have.

I know it would be cruel to post without pictures of the build and unfortunately I have none of the bathroom but here are some of the rest of the rig.

exterior with the dingy. .


interior I started with


what the interior is looking like now


older shot if interior showing kitchen area


It has all the features and functions of your standard Winnebago but we still need to add a hot water heater.

[qwcslvr1]

did you use a P trap for the shower drain? try plugging the shower drain and see if odor disipates

[mcurcio1989]

There is a P trap in the shower drain. I will try plugging that shower drain up. . unfortunately it isn't going to be as easy to plug as the toilet was.

My next thought is to put a dehumidifier in there and dry the bathroom out really good to see if it does anything.

[Kenn]

You said you are using a boat blower. Is the blower blowing air out of the bathroom and if it is, where is the air entering the bathroom. If the bathroom is almost air tight then the blower may be pulling air in through the vent and then up through the shower. If you could have positive pressure in the bathroom you may get rid of the odor. If you are blowing air out and you flush the toilet you are letting black tank air in. If you could have a two-way blower that may help. If you place a piece of soft rubber over the shower drain that may also help. Good luck Kenn

[mcurcio1989]

I don't think it is the blower that is causing the problem because the odor arises even when it is just sitting. You are right though in regards to sucking in air during a flush. I turn the blower off before flushing otherwise it will suck air out of the black. It doesn't have a good place to pull air from.

I suppose if we added a blower to push cabin air into the bathroom it would help some but I want to find the source of the odor as it seems like with a p trap and functioning toilet seal their should be no odors escaping. Do you guys think it is possible that perhaps just the damp air is causing the problem?

[qwcslvr1]

another thought I had was to simply run some water down the shower drain to see if you may have emptied it on your return trip, I used to have this issue with a transporter I had. Apparently certain rocking motion when traveling would allow my shower P trap to slosh enough water out that it would allow grey tank odor into the coach I just ran the shower for a minute and filled the trap back up and eliminated the odor source

[andyg]

lots of good advice so far. This may seem dumb but..... make sure that the vent pipe is not clogged with a bird nest, wasp nest, mud daubers.......

[mcurcio1989]

Checked the pipe and it is good. I have a bit of an update but with no results. I decided to drain and pull the tank because honestly this is just getting annoying and I need to take care of it. So I drained and flushed both grey and black really good and then pulled the tank out and set them in a different garage. Holy crap the smell in the black tank was agonizing however it is certainly not the smell that is in the bathroom. I'm gonna clean everything really good now but I kinda doubt it will help.

This sounds weird but I am beginning to wonder if the FRP just absorbed a funky smell. When this first started occurring their had been a bunch of dial soap spilled on the floor and it was pretty damp from taking showers in there. The smell is just like damp soapy smell with a hunt of sanitation odor. I just wonder if somehow it got absorbed into the walls. Its weird but it is all I can think off.

[bushpilot]

interesting comment about the tank smell when it was disconnected.

it might not be helpful but….my tanks NEVER smell when empty.

i come back from a trip, dump my tanks (rinse the black tank, ALMOST every time)
put it back in our storage garage (usually don't even bother putting deodorizer in the tank) and I've NEVER had an issue.

our coach sits for weeks sometimes i swear i could stick my head in that open toilet (valve open) and don't even as much as catch a HINT of odor.

even when i had the toilet completely off, open hole (rebuilding it & replacing seals) for 2 weeks i never got any odor in my coach.

[mcurcio1989]

^Interesting to hear I am going to give the black a good and thorough clean while it is out and hopefully remove the odor from it. Probably use more of this odoban stuff.

I guess just a little bit of ignorance and impatience got the best of me on the tank situation. We have let if sit for extended periods of time with sewage. When I was building it I used to regularly use it and the only place to dump is a half hour away hence it had sat for weeks and maybe months without getting dumped. I was really just unaware that it is a best practice to avoid letting them sit with sewage in them. I have never owned or even used an RV before this. I was also unaware of the biology / chemistry behind the odorizers and that once they have been in there for a week they aren't going to do much of anything.

I went over to the rig yesterday and it seems like the smell had not come back yet but more time will tell.

[bushpilot]

i tend to error on the paranoid side w/ these tanks - at least i did when we 1st got our coach….NOW, not so much.

Ours has sat for weeks on end (on my mother in laws curb) while we lived in the coach, and we never had an issue.

in fact the only time I've had a problem was on the same visit to my MIL's….i was unaware that the tank level/sensor wires had come off & was IMPROPERLY reporting that the tanks were EMPTY…not until we left my MIL's did we catch the occasional WHIFF of sewage…i discovered at a rest area that the tank was about 3/4 full….and i assume the agitation going down the road generated the odor.

when traveling or dry camping we make great use of the free dump stations in state rest areas (theres an app for that)….and I'm fortunate that my storage area has a dump station & wash bay.

[bushpilot]

i should also add that SURPRISINGLY the gray water can get a pretty nasty smell to it….considering its just soap and water (and i assume some SLIGHT/light grease or food from washing dishes).

If were dry camping for an extended period of time - I've been known to "leach" off some of our gray water (under the darkness of night)….disclaimer here…I've done this AWAY from others campsites and never in such a way that it would offend anyone.