Composting toilet installation in a T@B 400

Haloo · March 2018

I wanted to install a composting toilet in our T@B 400 before we used the OEM toilet and black tank. My longer term plan is to combine the black with the gray tank to increase our gray water capacity. Here are the high points of the installation

Step 1: Removed the sink panel and OEM toilet.

Image: https://us.v-cdn.net/5021717/uploads/editor/33/smmwpgkmwfdi.jpeg

Step 2: Install clean-out plug in blackwater tank outlet

Image: https://us.v-cdn.net/5021717/uploads/editor/rz/c97m6csditm2.jpeg

Image: https://us.v-cdn.net/5021717/uploads/editor/4w/izhjd0931md7.jpeg

Step 3: Cut out 3/4” plywood mounting plate for composting toilet

Image: https://us.v-cdn.net/5021717/uploads/editor/7o/918pt7btzrez.jpeg

My first install of the composting toilet was temporary. So there are some extra holes in the
mounting plate that I didn’t use for the final installation. I covered the plywood in linoleum and it got caulked into place.

Step 4: Drill a 3” hole for the vent fan through the side wall of my beautiful camper. Yikes!!!

Image: https://us.v-cdn.net/5021717/uploads/editor/kb/4702ous70vji.jpeg

No worries. It came out great. I used a stud finder to help me miss the studs.

Step 5: Install the vent fan housing and vent hose attachment sleeve.

Image: https://us.v-cdn.net/5021717/uploads/editor/c3/cm93ugoymbwi.jpeg

I snaked the wiring for the vent fan behind the sink panel and was able to easily keep it out of sight all the way to the battery. I have a pigtail attached to my battery for my Battery Tender. I used the same sort of connector to attach the wiring from the vent fan to the pigtail attached to the battery. It’ll do for now.

Step 6: Mount the assembled Airhead Composting Toilet to its brackets and to the vent sleeve.

Image: https://us.v-cdn.net/5021717/uploads/editor/2s/njpvyhgf29r9.jpeg

Step 7: Mount a stainless steel clamshell vent over the vent hole I drilled though the side wall.

The finished installation:

jkjenn · March 2018

Great write up!

jgram2 · March 2018

@Haloo Looks great! Remind me please which model of toilet you used?

Haloo · March 2018

Twojgrams said:

@Haloo Looks great! Remind me please which model of toilet you used?

Airhead. We chose it because the 400 has a wet bath and the Airhead has good seals that will keep out moisture while showering.

jgram2 · March 2018

Thanks. I thought I remembered water is the enemy of composting toilets, glad you found a good option.

Sharon_is_SAM · March 2018

You made that look easy Haloo!

Dalehelman · March 2018

Nice work. I don’t want to hijack this thread but could someone please explain the benefit to the composting toilets over the holding tank style.

jgram2 · March 2018

@Dalehelman Here’s the skinny: http://www.livesmallridefree.com/blog/benefits-of-having-a-composting-toilet-in-an-rv

Haloo · March 2018

Dalehelman said:

Nice work. I don’t want to hijack this thread but could someone please explain the benefit to the composting toilets over the holding tank style.

Here are our 3 primary reasons:

1. We can go about 2 weeks before emptying the solids tank.
2. It doesn’t use fresh water for flushing, so our fresh water lasts longer.
3. We don’t have to deal with dump stations and other people’s poor habits.

Since we like to boondock, 1 & 2 are most important to us.

Dalehelman · March 2018

Haloo said:

Dalehelman said:

Nice work. I don’t want to hijack this thread but could someone please explain the benefit to the composting toilets over the holding tank style.

Here are our 3 primary reasons:

1. We can go about 2 weeks before emptying the solids tank.
2. It doesn’t use fresh water for flushing, so our fresh water lasts longer.
3. We don’t have to deal with dump stations and other people’s poor habits.

Since we like to boondock, 1 & 2 are most important to us.

Makes since thank you

icolquhoun · March 2018

Nice write up, thanks!

We will be installing an Airhead in our 320s soon (before the black tank has ever been used).

Do you find the platform in the corner of the 400 to raise the toilet to an uncomfortably high level?

For ease of install It'd make sense in the 320 to leave the existing showerpan but the perfectionist in me is looking for a flat pan. (I also haven't seen how the black tank is mounted under that bump)

Haloo · March 2018

@icolquhoun, it looked like it wouldn’t be a good idea to remove the OEM toilet mount unless you plan on removing the black tank. We chose to keep the black tank for two reasons: 1) If we ever sold our 400 the OEM toilet could fairly easily be reinstalled, and 2) We thought we might convert the black water tank to use as another gray water tank. The way the black water pipe attaches to the OEM toilet mount convinced me to leave it in place.

I actually could have used 1/2” plywood for less height, but went with 3/4” for sturdiness and to make it easy to use fastners in a way that doesn’t mar the floor.

To deal with the increased height, we have a little collapsable foot stool that sits on the floor and tucks away beside the toilet when not in use. (Google: pottysquatty)

All things considered, a composting toilet comes with a set of tradeoffs. It’s not necessarily less of a hassle than a conventional toilet, it just has different advantages.

ChanW · March 2018

@Haloo, thanks for that in-depth write up.

I've been highly sceptical of 'composting' toilets ever since I was the caretaker of a communal one at a summer cottage. Educating people on its use was impossible, and I had to deal with what 'remained', so to speak, at the end of the summer! Not pretty.

You've pointed out its useability for camping, and successfully got me past my bias! Thanks.

Keep up with proper stirring!

ColoradoJon · March 2018

Hmm. I'm still unconvinced to the benefits of a composting toilet in these small campers. The link @Twojgrams posted lists some benefits, but nothing that strikes me as 'gotta have'. In fact, some of the info does not even apply - they guy uses the water volume per flush of a household toilet, not a RV toilet! Kinda biased I'd say. Not having to dump at a dump station is awesome, though. But... don't you have to dump a composting toilet? Seems like apple and oranges in the same bag (different things but essentially the same at the end).

This is a great write up, though. Good job @Haloo

ChanW · March 2018

@ColoradoJon, yeah the composting toilet needs dumping, but theoretically, it'll be somewhat dry, as the evaporation of moisture is a big part of the design.

In the one that I was responsible for, we put peat in there to help absorb and distribute the moisture, so it would dry more quickly (theoretically). We also put a bit of soil in there to introduce microbes (I doubt that will be happening in an RV though).

The use of a "composting" toilet in an RV situation is actually a misnomer, because there won't be enough 'digestion' time for the actual composting.

So it ends up being a "dry" toilet, sort of, with the difference being dump method and location, and frequency.

@Haloo figures two weeks between dumps, which, if it turns out that way, is a good alternative to dump stations. The hose has worked ok for us, but finding a dump station is sometimes a burden, so I can see the attraction of the dry toilet, as long as the dumping of the 'bin' is designed to be easy and mess-free.

Haloo · March 2018

@ColoradoJon
@ChanW
Before we bought our 400 we had already decided we wanted to be able to install a composting toilet. We travel and camp mostly in the west, and mostly in remote areas where there are no dump stations. You have more options for dumping a composting toilet than a conventional RV toilet. And we will have to dump less often.

There is a certain amount of unpleasantness with either a composting or conventional toilet. We’ll just have to learn new habits with the composting toilet. But there are so many folks who have used these toilets in RVs and boats, and posted write-ups and videos, that there is little mystery about whether and how they work.

We’re hoping to learn how to get the most out of the 200 watt solar package that came with our camper. With solar and a composting toilet, we hope to be able to hang out in places we like for as long as we like.

HR_Taly · March 2018

@icolquhoun I have installed an airhead in my 320 back in July and been using it full-time since. The marine size one fits perfect.

I don't necessarily have a platform (a bit of one to level it off), but the toilet section is raised and the airhead does sit up high. I was concerned at first, but it's actually quite er, usable. I had mine installed in July, I really do have to get around to posting the write up on it.

I think another person had taken the whole shower pan floor out to do some replacements and posted some really good pictures of what's under a 320 S shower floor if you want to do a major (but good) install of one in a 320S.

Feel free to message me or start another post so we don't confuse the 400 folks or derail their thread!

*****Note to others: HR__Taly has sold her T@B and returned to her homeland. She is no longer on the forum, and therefore she will not be answering questions *****

Haloo · March 2018

@HR_Taly, as I remember, you are doing some boon docking, yes? Can you give me any feedback on the power usage of the vent fan? Are you using solar panels? Generator?

HR_Taly · March 2018

@Haloo - yes, I'm almost exclusively boondocking. I've 160 watts of solar on the roof and dual 6v batteries for 225ah. The small fan for the Airhead vent apparently only uses 0.1A so it's quite the energy miser and I don't even notice it. I often have to hold my hand under the vent outside to make sure it's still running!
I think airhead does make vent caps with a small solar panel/battery inset in them that can actually run the vent without having to tie it into the existing 12v system, but likely you'd need to vent through the roof to get appropriate sunlight (this is mostly for marine installations which is their main focus).

*****Note to others: HR__Taly has sold her T@B and returned to her homeland. She is no longer on the forum, and therefore she will not be answering questions *****

Haloo · March 2018

HR_Taly said:

@Haloo - yes, I'm almost exclusively boondocking. I've 160 watts of solar on the roof and dual 6v batteries for 225ah. The small fan for the Airhead vent apparently only uses 0.1A so it's quite the energy miser and I don't even notice it. I often have to hold my hand under the vent outside to make sure it's still running!
I think airhead does make vent caps with a small solar panel/battery inset in them that can actually run the vent without having to tie it into the existing 12v system, but likely you'd need to vent through the roof to get appropriate sunlight (this is mostly for marine installations which is their main focus).

Excellent! We have 200 watts of solar and a 235ah 12v battery. While I can definitely hear our fan, I don’t think it is drawing much more power than yours. The Wynns (GoneWithTheWynns.com) say their fan drew 1.7 amps in 24 hours. In any case, I think I don’t need to worry about the fan’s power consumption.

We are headed out on Monday and will be putting our composting toilet into action for the first time. Sure is nice to know we don’t have to worry about dump stations and monitoring a black water tank.

Thanks for your comments here and on other threads about your composting toilet.

ColoradoJon · March 2018

Wow, this is really good information. Thanks @Haloo, @ChanW, @HR_Taly

I'm about to close on 35 Acres of land that has a well and a small shed for solar equipment and bathroom. I was thinking about a composting toilet for that bathroom.

When you dump these, where can you dump? Do you simply dump in a heavy duty bag and out with the trash?

Haloo · March 2018

ColoradoJon said:

Wow, this is really good information. Thanks @Haloo, @ChanW, @HR_Taly

I'm about to close on 35 Acres of land that has a well and a small shed for solar equipment and bathroom. I was thinking about a composting toilet for that bathroom.

When you dump these, where can you dump? Do you simply dump in a heavy duty bag and out with the trash?

Here is a great article on the use of a composting toilet. About half way through the article he addresses the issue of dumping the toilet contents.
https://boldandadventurous.com/Life-with-a-composting-toilet/

This author seems to agree with the many articles and videos I’ve viewed on the subject. In short, you have more options for dumping than an RVer has with a conventional toilet.

ColoradoJon · March 2018

Thanks, @Haloo. I'll have to look into these further.

ChanW · March 2018

And definitely watch the Squatty Potty ad....OMG.

https://youtu.be/YbYWhdLO43Q

k4man · August 2019

@Haloo, I think it's been over a year-and-a-half since you installed your composting toilet and I wanted to check in with you about how it's working out? Last month we purchased a 2020 400 Boondock and I'd love to replace it with a composting toilet. How long of a job did it end up being, 1 day, 2 days, a week? Did you ever end up combining the black and grey tanks for added grey tank capacity? We've been using our black for the past 2 months and I'm guessing I'd have to pull mine out and replace it with an additional new grey. I'd love to hear how it's going. Thanks.

fishergary · February 2020

@HR_Taly , I'm planning on ordering an Airhead toilet for our 2019 Tab 320. From your picture, it looks like you have the crank handle on the inboard side (right when facing the toilet). Would you advise getting it configured this way? Also, it looks like the Household Seat only protrudes about an inch further from the back than the Marine Seat, and would still be more compact than the stock toilet, so I'm considering going with the Household Seat option. Based on your experience, would you advise for/against that? Do you have any other comments or advice?

Thanks.

Denny16 · February 2020

Seems like more work, for a small gain, that only changes how you end up dumping a toilet. While the Compositing toilet gives more dumping options, using the old bag in the existing toilet for a “dump as you go” would be the best option for extended Boondock camping, or where dump stations are not readily available.
cheers

Verna · February 2020

*****Note to others: HR__Taly has sold her T@B and returned to her homeland. She is no longer on the forum, and therefore she will not be answering questions *****

Haloo · February 2020

@fishergary , you can swap the handle to the other side if you need to. Otherwise, I have a 400 so can’t advise specifically regarding the seat in a 320. We have the smaller seat in our 400, and the larger seat in our boat. I haven’t noticed any real difference in use between the two, other than the lid on the larger seat needs more room when up. My wife and I are not large people.

@k4man , sorry for the very long delay in responding. I’m sure you’ve made some kind of decision by now. Anyhow, we’ve now used our Airhead composting toilets in our 400 and on our boat for over 2 years. They have worked wonderfully and are very easy to manage. There isn’t another toilet we would prefer.

gspdx · February 2020

Thanks to everyone for all of this info. Definitely something we are thinking about. We plan on doing quite a bit of boondocking and not needing to dump as often and not using water to flush are pretty big gains.

The idea of re-purposing the black tank to house grey water is an interesting idea. It seems that the black tank is completely above the floor and the grey tank is completely below the floor so just trying to tie them together could be a problem. Anyway - if anyone has a solution it would be interesting to hear!

fishergary · February 2020

@Haloo , Thanks for the response - I think we'll go ahead with the standard seat. Good to hear we can switch the handle side if needed, and great to hear that you're so happy with the product

@gspdx , I've been evaluating options for repurposing the black tank for some time now. These are the options I've considered:

1) Combining black and grey tanks.
- rejected this due to the height of the black tank - as soon as the black tank would start to fill, water would flow into the shower pan.

2) Converting the black tank to an additional fresh water tank.
- because our tank has never been used, this would be possible, if only used for washing (the plastic in black tanks isn't approved for drinking water). However, I think the effort required to add a pump and get everything plumbed in and switchable between the 2 sources would not be worth it to add another 8 gal of fresh water.

3) Remove the black tank and add another fresh water tank in it's place.
-after looking at the underside of the trailer, it seems this would be very difficult, if not impossible (someone correct me if I'm wrong)

4) Re-routing the drain from the sink into the black tank, making it a second grey tank. The main grey tank would then be used only for the shower. A valve could also be added to allow switching the sink drain between the new line to the black tank and the original line to the grey tank in case the black tank fills first.

5) Converting the black tank to a "yellow tank". I understand the Airhead has the option to connect a hose to the bottom of the liquids container. This could be easily routed to the black tank directly below. This would eliminate the need to manually empty the liquids tank every day or two. I would guess this would allow a full week or so for 2 people before needing to be emptied.

So I'm debating between options 4 and 5. I'm also thinking I could do both - use valves to switch between the 2 options.

Howdy, Stranger!

Quick Links

Categories

Composting toilet installation in a T@B 400

Comments