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Old 01-14-2020, 09:09 PM   #1
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Why Can't I Install A Residential Toilet?

The electric (12V) Concerto "China Bowl" toilet is really nice, but I suspect it will need maintenance one day and that's hard to come by.

You can sometimes find parts and fix it yourself, but sometimes this toilet still will not work right, because you think you identified the right part to repair and then you find out you were wrong... and the parts are expensive.

So... Why Can't I Install A Residential Toilet? (See Sublime II dimensions below.)

You can buy this Sublime residential toilet at Home Depot for $250 and it's a one-piece toilet that is only 24" deep (from the wall) vs. my Concerto RV toilet which also 24" from the wall. And this Sublime II toilet has a 0.8gal flush option so that's not bad. Maybe not as good as the Concerto, but I never seem to fill up my back water tank before I need to dump... so why should I care about the 0.8 gal/flush?

Does anyone know how much water does my Concerto use with the water I spray out of the wand?

Sublime II made by Swiss-Madison. (I never heard of them, but no matter. They are getting good reviews!)

The Sublime II calls for a 12" cut out vs. the Concert floor cutout which calls for 11-5/8" from the wall. Of course, I do NOT know what my RV floor cutout will be until I pull the toilet. Can anyone tell me?

I'm thinking I can always install an "offset flange" if I need to, but again it would be nice if anyone else has installed a residential toilet and can tell me what surprises I might find.

I do plan on adding an on/off valve and I will need to pick up some plumbing parts to make the necessary hose connection/reduction, but I suspect this is all manageable?

As for the increase in water flow, I am not concerned about that since I'm never filling my black water tank before I run out of water "on the road" or when I am boondocking; and when I am in my summer RV camp spot I have electricity and a dump tube.

...So why aren't more RV owners putting residential toilets in their RV? Is that because, up until recently, all residential toilets were 26-28" deep and that would mean they would take up too much room in the small toilet closet?

This toilet has the same depth or will be 24.5" from the wall when done, and I can live with that easy. And when I am driving, all have to do is flush and turn the water off so it does not fill the bowl. Either that or I can adjust the fill so the tank only 1/4 of the way up in the bowl or I can add a baffle to stop the water from sloshing out. Maybe just covering with seran-wrap will work will? TBD

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Old 01-14-2020, 09:16 PM   #2
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Why not just install a rv toilet that isn't electric. I have never understood the need for a power toilet anyway.

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Old 01-14-2020, 09:17 PM   #3
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I'd be more concerned about the water in the tanks sloshing than the water in the bowl.

The answer to your question is the tank. Adds a level of drive prep and unprep to use the toilet while traveling such as when you stop for lunch. With an RV toilet all you have to do is turn on the water pump for a potty break when you stop.
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Old 01-14-2020, 09:23 PM   #4
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For one thing, home toilets hold a bunch of water, both in the tank and bowl.

That's going to slosh out while traveling. You can drain most of the tank water, to fix that problem.

If you drain the bowl, there will be an open passage thru the bowl trap to the black tank. That's going to let waste tank orders and gasses enter the RV.

RV toilets seal the smell and don't hold much water above the seal.
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Old 01-14-2020, 09:32 PM   #5
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One more point besides the sloshing while driving is that you will just run out of fresh water that much sooner. I don't see the advantage to a residential toilet.
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Old 01-15-2020, 01:13 AM   #6
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If you could install a residential toilet for $250, would you?

Thanks for your quick replies.

It would appear that many on this forum will have a strong opinions about this subject. Maybe this is why a toilet has been dubbed a "thrown." I.e., the "haves" vs. "have-nots!"

In my case, I think I spend about 3-5 months every year in my RV and so my thrown is important to me. And the thought of the Concerto toilet malfunctioning is now on my contingency list. Why? Well, because I can't do without a toilet when I'm on the road and I have no mailing address to receive parts. And it's not like any RV carries Concerto parts. (None in fact!)

The Concerto is a great toilet and it's expensive to replace. So if my Concerto brakes I have no plans on fixing it. Why? ...Well, as I said parts are expensive and I can't work around a 5 + day turnaround to get parts delivered -- even though I can install those parts myself. So I need to have a contingency plan in the event my Concerto dies on the road.

That... and in general, anytime I throw money a problem I think about how to "upgrade" or make the item being repaired better.

So maybe I need to rephrase my questions on this subject? Maybe I should have asked, "If you could install a residential toilet for $250, would you?"

I think the only factors "bucking" your immediate approval of putting a residential toilet in an RV are these. So let's review them and see what's changed in the market today... to see what's stopping you from trying?

1) Space

==> Prior to 2019, all the residential toilets I saw in the stores and on-line were 26-28" away from the wall (deep). But now we have 1-piece toilets, and this is the first year I have seen a 24" deep toilet that is not a "tiny toilet" or a "kids toilet."

The toilet I just found today is called "Sublime II"...and above is the link to a HD website where you can buy one for $250. And Amazon also sells them.

2) Water Consumption

==> Residential toilets are now 0.8 gal/flush for econo flush (6.4 pints) and you have an option for 1.2 gal/flush.

==> I am told a typical RV toilet (using a spay wand) will use ~3 pints of water per flush. So that means your black water tank will fill-up 2-3x as fast if you convert to a 0.8 gal/flush toilet... which has a p-trap built into the base of the toilet... a real plus if you ask me since that water in the p-trap will block all smells just like it does in your home!

...But as I said, my black water tank is always 30-40% full compared to my gray water tank when I am ready to dump.

So this means, if a residential toilet does flush 2x-3x more water, then the volume of my black water tank now holds (over a 3 or 4 day period), which it should be able to do, because by then I will need to replenish my water tank anyway -- and that's when I normally have a chance to dump the black and gray water.

Note: My Gray Water tank is 48gal and my Black Water tank is 52 gallons. So I should be okay with the extra water going into the black tank.

If I do add a residential toilet with 0.8GpF, then I do concede there will be less fresh water for showering! ...So how much water are we talking about?

I think we flush about 40x over a 3-4 day period. That's 6 flushes per day; times 2-3 extra pints of water/flush; or about 72-100 pints during the roadtrip (or boondocking period) which works out to an approx. 7-9 gallon penalty to install a residential toilet.

So the real question to ask now is: How often would you miss NOT having 7-9gallons of fresh water for showering or washing dishes? And keep in mind you have a 100 Gallon water tank? So we are taking about a 7-9% less water than you use right now, but you will have a residential toilet!

===> For my use, I don't see this as a problem. However, if you always find yourself running out of fresh water on your camping trips or on the road, then I would say a residential toilet is NOT for you!

3) Installation to center of floor flange (typically 12" from the wall).

==> A residential toilet typically requires 12" from the wall.

==> My Concerto toilet spec calls for 11-5/8" from the wall

==> Therefore, I should be able to mount the Sublime II toilet tight against the wall, and it should fit with the non-wax ring or an offset flange. So I don't see a problem with installing a residential toilet in an RV. (TBD)

==> I also don't see a problem hooking up a water valve and matching the thread types so I can turn it off.

==> Maybe I can even add a "shark-bite" on-off valve that should work very well. (TBD)

4) Traveling with water in the bowl and in the tank. What to do about that?

==> Is this really a problem? I don't think so. Here's why: I see no problem turning off the water and then flushing the toilet. This will remove all the water in the tank and after a flush the bowl will not refill with water.

This action also means a siphoning action will suck water almost out of the bowl, but will leave a small amount in the bottom of the bowl... enough to fill the p-trap in the toilet base -- and stop all black water smell. Think of that? NO MORE BLACK WATER SMELL!!

Try it in your home yourself. Just turn off the water at your wall-valve and flush your toilet. Then you will see how little water is left in the tank and in the bowl. ...So I think we are good here. I.e., I don't think any water will slosh out of the bowl when driving.

==> But what-if I don't want to turn off my water. Here's my thoughts on that and why I don't want to turn off my water?

Solution: I will adjust the water height so the water is only 1/4 tank full. This will be enough to use for a short flush anytime I want without turning the water back on. And the water will not slosh out to the tank, because I will make a plastic baffle to put in the tank just above the water high mark. And when I turn a corner, the water does not slosh out of the top.

First I need to confirm a baffle is even necessary. It might turn out that just filling the tank 1/4 full will not let water out of the tank as I drive. ...And it might turn out that the water in the bowl will not slosh out either since the rim of the toilet will block that action.(TBD)

... And then, when I get to my camp spot, where I will have water and sewer hook-ups, all I have to do then is re-adjust the water height so the toilet will do a full flush at 1.2G/F.

My problem is that my coach is in storage until April/May, and I live a few thousand miles away. So I will not be able to perform this upgrade until then.

However, if anyone reading this thread can follow my lead and pick up one of these 24" deep toilets at Home Depot for only $250, then maybe you can beet me to the punch!

And just because no one is installing residential toilets in an RV does not mean it's not a good idea. They said the same thing about residential refrigerators and now every new RV has one of these babies! And most everyone who has ever had a residential refrigerator in an RV will never own a absorbtion-gas-fire trap again!

Honestly, everyone deserves a thrown! To say nothing about how happy your wife will be when you chuck the plastic porta-potty away and give her (and yourself) a real china bowl toilet that is easier to clean -- and which sits 16" high! And that's another benefit everyone will like... especially if you are over 60!

So encourage all you naysayers to think about it, and then be honest with yourself and others who read your comments on this forum: Would you really want to keep using a plastic or mechanical RV toilet... and deal with those familiar black water events from time-to-time on the road... or would you seriously like to have a full size toilet you can flush... like at home... that almost never needs servicing and is easy to clean? ...For only $250!
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Old 01-15-2020, 01:31 AM   #7
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Originally Posted by spdracr39 View Post
Why not just install a rv toilet that isn't electric. I have never understood the need for a power toilet anyway.
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Old 01-15-2020, 07:03 AM   #8
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Lid sliding off the tank while moving might be a problem.
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Old 01-15-2020, 07:12 AM   #9
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….reference post #6--I had no idea there was so many things to consider when selecting a toilet----wow--it really is a "throne." Water consumption is also an issue for traditional goose-neck toilets....
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Old 01-15-2020, 07:16 AM   #10
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Sounds like your mind is made up but you don't have to spend more than $100 on a "toilet-to-go" at the big box store.
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Old 01-15-2020, 08:09 AM   #11
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Originally Posted by Jim18655 View Post
Lid sliding off the tank while moving might be a problem.
If you drain the tank and the bowl when traveling and store the lid some place "safe" go for the residential toilet.

Some of the newer residential toilet have a large hole between the tank and the bowl for "better flushing" ! It really does help !!
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Old 01-15-2020, 08:18 AM   #12
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Big mistake

A ceramic toilet is heavy and bolted to the floor with just 2 bolts.

A house is stationary and the bolt down is just enough to keep in place during use but now you want to put in a moving vehicle. There is no way to hold it down securely in this application.
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Old 01-15-2020, 08:27 AM   #13
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You might want to double check the numbers on the gallons in your gray and black tanks. It would be a very rare animal indeed to have a larger black tank than a gray tank. If you do, then maybe the shower or something else is plumbed into the black tank. As a general rule, most rvs would be 60 percent gray, 40 percent black.
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Old 01-15-2020, 08:36 AM   #14
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Use the KISS principle. Keep It Simple Stupid. Just install a good grade of a foot pedal flush RV Toilet. I see too many negatives to a residential toilet. Too much water usage, Too much chance to slosh water.


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