View Full Version : What's the quietest rear outlet toilet?

10-27-2007, 02:39 PM
I'd like to replace my floor mounted rear outlet toilets (Kohler Barrington two-piece with Flushmate pressure assist top tanks). I cannot change the rear discharge plumbing. I have four toilets to change out.

The problem is that the pressure assist systems have all of the quiet charm of a hand grenade. Especially at night!

I really need something quiet, that works well, yet looks good.

My questions are:

1. Do i have to use power "pressure" assist with a rear outlet toilet?
1a. Or is it at least highly _recommended_ that I use power flushers?
1b. Or is a well designed gravity flush feasible? (that would be quiet!)

Because of the change to 1.6 gallons, you can no longer find a gravity tank that works as a floor mounted, rear outlet bowl.

2. Does Toto make a rear discharge toilet? What's the model? I can't find that from their web site.

TOTO does not make a floor mounted rear outlet bowl.
They do make commerical bowls that use a Sloan type valve that use a wall carrier.
These would not be recommended for homes. To use any commerical flush valve in a home would require repiping the home all the way to the water meter.

3. I've heard of some electric toilets that seem to combine some sort of power assist flushing, yet are reasonably quiet. Do these exist? What are their advantages and disadvantages? Would any of these kinds of products apply in my case?

None of the electric toilets are floor mounted rear outllet bowls.

3. What manufacturers and models would you recommend?

I'm remodeling, and the tiling is due to go in in a month or so, so i have a chance to add electric and make a few changes, but the rear wall plumbing has to stay (it's inside cinder block concrete).

Thanks, TC

10-27-2007, 03:47 PM
High wall mounted tank and gravity flush?

10-27-2007, 05:16 PM


i have a duravit Happy D wall hung, and plumbing with venting before the SanTee.

It doesn't even need to make much of a siphon effect to flush smoothly and quietly. That happens a lot more when there is less venting (or a Wye fitting). The pipe configuration behind the toilet adds to the complexity of your calculations, by the way, in case you are looking for objective third-party standards. In terms of flush (timelength, volume+height of water) and noise of flush

i guess a rear discharge floor mount will be out there somewhere. Use those four words in various search engines.

No to flush valves.


10-29-2007, 02:32 PM
Thanks, I'm looking into the Happy D. I can't hang it on the wall, it needs to be a floor mounted (say 4" rough in) unit.

For such a rear outlet set up, will i need to have a cistern way high up to generate the required flushing force? I'm not sure if the builder installed the power flush tanks to save water -- or because he had to in order to have the air pressure so has to empty the bowl.

That is, if the builder installed the power flushers just to save water, is it at all feasible to install a rear outlet toilet that does _not_ have a power assist?

If not, then what I'm hearing is that i need to have the cistern high up so as to generate a more powerful gravity assist.

Thanks for the illumination and advice here.

11-02-2007, 09:21 AM
There's a few models listed in this thread (http://www.terrylove.com/forums/showthread.php?t=12796). I bought the Crane Economiser model, but haven't installed or used it yet.

11-12-2007, 11:55 AM
So it appears that other than the Happy D, most rear outlet or rear discharge toilets use some sort of power flush mechanism inside the tank.

The Happy D seems to use a gravity feed scheme, which is what I'm after.

So, to confirm: with a rear outlet toilet and conventionally attached tank (say a one or two piece set up) do I ***have to use a power flusher***?

Is it that the way the disharge works (the pipe out the back) _requires_ that the power generated by the air/water blast that the Flushmate or Ecoflush power units generate?

Is my only gravity option to use a tank (cistern) that is mounted high off the ground? If so, how high from the bowl must the tank be?

Thanks again,

03-03-2009, 03:59 PM
Yes. Old thread but in case others are searching I bought the Crane Flormont (Model: 3186) which is a Bowl: 3184 Tank: 3546. Total crap. and its old and ugly looking. Had I known I could have bought the Duravit Happy D and a in wall tank I would have SURELY gone that way. I'm super jealous now that I've seen one installed. Same money too, the crane cost me approx 400.00.

Question: My condo doesn't allow the newer power assisted toilets thats why I bought the Crane. Could I have bought a Gerberit concealed tank alongst with the Happy D and made out fine? I'm considering redoing at least one toilet if this is in fact the case. Thanks!

08-30-2009, 07:23 PM
I've just done EXTENSIVE research on rear exit toilets and the choices are horrible - American Standard Yorkville is the only Comfort Height and at least one of the models is being discontinued 10/09, per their catalogue. I can't get a clear answer from American Standard about the others. Then there's Crane, Gerber (which everyone seems to hate) and Kohler.

If you can't install a Duravit (I can't - shared rear outlets), you're not only stuck with noisy and power assists that people who have them hate but they're HUGE - ~ 30 - 32" long - which is a real problem if you have a small, urban bathroom.

I don't know who decided the world needed longer toilets.

I'm actually debating about leaving my 30 year old American Standard and giving up on a beautiful pure white sink for a boring bisque pedestal because it would match the toilet. Or even looking for an old pure white toilet.

This is NUTS

10-05-2009, 09:44 AM
We are also in need of a pair of floor-mounted rear exit toilets for the renovations of our condo in 1832 building (i.e. no moving of drain pipes allowed).

I do not want a wall mounted toilet like Duravit, etc for numerous reasons.

We are looking at Crane Flormont line. Specifically a 3932 model which is a 17" gravity fed bowl. It is very inexpensive. I specifically want to avoid power assist models like American Standard Yorkville, Kohler Barringron, etc for noise reasons.

So, has anyone installed and used Crane gravity fed toilet (several other models would be 3931 and 3930 with lower bowls)? If so, does it flush well enough? Any other comments on it? How's Crane quality overall compared to others?

Thanks in advance for your answers. We need to chose something very quickly.

PS. Caroma just release a new floor mounted rear wall toilet a month ago. We don;t like the modern look and seat, but it might be what someone is looking for.

10-26-2009, 12:57 PM
I am about to replace my second Crane Flormont 3116 toilet this year. I have the misfortune of having a rear outlet toilet in a small bathroom and couldn't fit an elongated bowl. The Crane was the only toilet I could find to fit when we remodeled the bath. The first one never had a decent flush. A small hairbrush fell in it and got lodged in the pipe and the plumber couldn't dislodge it. We replaced the bowl with the same Crane product. I would have changed the entire toilet as it never had a good flush on its best day, but I was still unable to find one. 13 months later the toilet can't flush solids and the plumber replaced the tank mechanism and has snaked it (removed from floor/wall for snaking) and I am looking at replacing it again.

Does anyone have experience with the Caroma Rear Outlet toilet that was mentioned? Or do you know of a rear outlet round bowl toilet that might work better than the Crane?

10-27-2009, 03:47 PM
So... Is pressure-assisted toilet the only way to go for rear outlet? Anyone?

10-27-2009, 04:40 PM
If you have a floor mounted rear outlet bowl, then most are going to be pressure assist.

If you are looking for a wall mounted bowl, then you can find gravity bowls in some of the in-wall tanks, and with the Crane Rexmont wall hung toilet.
The Crane Rexmont doesn't work very well though.

The American Standard Glenwall pressure assist works pretty well for a wall hung toilet.
Not really quiet, but not too bad either.

Some of the old Kohler pressure assist bowls were quite loud.
The newer Kohler bowls with pressure assist are much quieter then those.

Caroma Sydney Smart back outlet, Gravity

Here is the Gerberit in-wall system


10-28-2009, 12:15 PM
I am now looking at the Duravit Happy D D14023 with Vario outlet that supposedly can be rear outlet installed. It is a floor standing model, not wall hung, unless I am mistaken and is not pressure assist. Does anybody have any experience with this product to evaluate its flushing power, and would it fit as a replacement for my terrible Crane Flormont 3116?

10-28-2009, 06:13 PM
Terry, I would very much like to stay with floor-mounted toilet for aesthetic reasons. The question is do I risk it with Crane Flormont, or, perhaps, get one Flormont and one pressure-assist (Kohler, Zurn, American Standard Yorkville, etc)?

I've seen Duravit Happy D, but am concerned with the euro-look and lack of seat choices other than the one that comes with it.

10-28-2009, 09:05 PM
My plumber said that the Duravit Happy D will not work for me because the outlet is at 8" and my wall outlet is only 4". Too bad, as that seems like a really nice product and is narrow enough for my space.

I am now looking for opinions on the Caroma Sydney Smart back outlet. The 4" trap seems like a big advantage as I have serious clogging with my Crane Flormont with its 2" trapway - caution to Mike S, that is a really poor product. My concerns about the Caroma are 1) the low water - is there a lot of staining on the inside of the bowl and is there sufficient water to wash out the solids? and 2) the pipe that connects the rear outlet to the wall - is it very ugly and are there issues with leakage as there are no bolts connecting to the wall?

Are there any pressure assist 4" rear outlet toilets with a round seat under 28" long?

11-05-2009, 07:21 PM
I was also looking at Caroma and for the life of me do not understand that rear pipe. Does it simply sit there exposed?

Is that toilet even available yet? They've announced it in late August, but I have not seen anyone selling it.

I had no choice, ordered one Crane 3191 so far. At only $200 it's cheap enough to try. The problem is that we need a second toilet before we have a chance to try the first one.

11-06-2009, 03:46 AM
I have the Caroma Sydney Smart Rear Outlet on order and it arrives today, so I will let you know what I think after it is installed. I ordered it through theenergyconscious.com though I could have probably ordered it locally. I found the owner very helpful in answering my questions and used them. I also watched the videos on the Caroma website so I understand the flushing principle better. I have been assured that it won't clog despite the 1.3gpf due to the washdown flush and 4" trapway. It is also supposed to be quiet.

The exposed rear outlet pipe runs from the 4" rear outlet to the wall. In my bathroom it will be hard to notice, but I think it would be more visible in a bath where it is seen from a side view. In my case it is head on when you enter the bathroom. It is not the most beautiful toilet ever but neither was the Crane and that didn't flush properly.

11-12-2009, 04:25 PM
Some pictures and a little review would be great.

In the meantime, I had a chance to use a Caroma (not rear-outlet) in an office a few days ago. A bit loud, but decent. My biggest issue with it was a thin seat. Very european/asian feel to it, some people like it, some don't.

So, we're waiting for your impressions!

11-16-2009, 06:22 PM
My Caroma Sydney Smart 1.3gpf Rear Outlet Dual Flush toilet was installed today. It fit perfectly in the limited space; although the seat is slightly elongated, it fits in the same 26" depth as the Crane it replaced. The rear outlet pipe attached perfectly to the wall drain. It hasn't gotten much use yet but seems to flush more than enough to clear the bowl both at both flush levels despite using only 1.3 gallons. It is no noisier than any other standard household toilet. The 4" trapway is huge and I think will solve the clogging problems we were having with the Crane Flormont. I am very impressed with the Caroma and will consider it for other replacements we are planning, even without the rear outlet issue we faced in this bathroom.

Luckily it is difficult to see the rear outlet pipe because the toilet is directly in front of the door in a small bath. If you bend over to see behind it, the pipe is definitely ugly. I can live with it considering that most people will not be inspecting the back of my toilet and it works so much better than the previous toilet.

12-14-2009, 06:10 AM
Has anyone looked at this toilet?

It's strong enough to flush into the mascerating unit horizontally that pairs with it, so why wouldn't it work to just run into the drain pipe that runs behind it?

The outlet is also WAY off the floor, so it'd allow a bit more distance to gravity feed to the stack.

Its bowl is the SANI003 and the tank is the SANI007. It's only a 1.6 gal tank, but I'm sure its gravity not pressure assist. But for < $200 it seems like an option I'd like to explore.

I've attached a picture. It says to use a 3/8" slope for the 15" extension which is just beyond the 1/4"/ft typical for horizontal runs.

Thoughts on this?

UPDATE: Called Saniflo... their toilet IS gravity fed (as i suspected). The extension pipe shown in the picture is metric sized. The end in the wall is 99 mm OD ~3.9" Their technical assistance guy said as long as there's a 1/4" slope, you can feed it wherever you want. Am I asking for trouble?

10-15-2010, 10:21 AM

I went out on a limb and installed the Sani-Flo toilet this summer in our basement. You can see from the picture that the toiled mounts to the floor and ties into a long radius 3" PVC TEE. The 3" rubber coupling is sized for the OD of a 3" PVC fitting (not 3" PVC pipe). It just took a little fancy work with some leftover baseboard to cover up the large hole in the drywall. This toilet is GRAVITY fed! It flushes by literally dumping the entire contents of the tank into the bowl in one violent deluge.

No clogs.... we're about 7' from the main stack!!

Hope this helps someone!


02-04-2012, 07:12 PM
I have a couple quick questions on this thread.

In the first post Terry says that because of the change to 1.6 gallons you can no longer find gravity tank that works as floor mounted rear outlet.

I said "most" of the floor mount, rear exit toilets were pressure assist, not all.
And then I went on to list those that were pressure assist and those that were gravity.

In my condo I am pretty sure what I have is the Crane Flormont 3932N - and according to the specs online it is "gravity fed siphon jet flush action" - does that mean it is gravity and not pressure assist?

If I were to try to replace it with the Kohler Barrington Pressure Lite I have 3 questions:

1. Would there likely be any issues with my condo building in doing this? Would it affect other units?
2. Would it be significantly louder than the Crane I have currently?
3. It says that the Crane has a 4 1/8" high mount on the wall and the Kohler says 4" - is this fine? Will it fit properly?

thanks so much in advance!


02-04-2012, 07:22 PM
The measurement from the floor to centerline of the flange is critical. You would probably have to shim the toilet up 1/8
No other part of the building should be affected
Since the new toilet is pressure-assist, then yes it is considerably louder\

A siphon-jet is NOT pressure assist. It just means the principal flush is from a hole right in the throat...water rushing in there starts the flow and the siphon action. This is the most common flush today, at least in my observation

Gary Swart
02-04-2012, 09:31 PM
The answer to question #1 will have to come from your condo association. As I understand it, many condo associations have very stringent rules on what is and what is not acceptable.

03-31-2012, 09:31 AM
What we won't do for simple convenience. Of course, some of you do not have a choice.

I have considered putting in a toilet in my garage but did not want to break out the foundation or floor concrete. Reading over this and other threads, I may just put in a urinal and go to the house for the other . . .