Back to back toilet: I bought a TOTO Ultramax II , now when flushing it the water level in the other one goes down & up briefly

[Costa]

Hi,

It looks like there is some suction effect that affects the other toilet.

Is this something I can live with in long run, or do I have to fix the connector? Fixing the connector would probably be easily a 4-5k job, which I didn't budget for.

Or maybe I should get another toilet that uses less pressure ? Do you have any recommendations?

Other ideas? The house was built in 79 or 80. I can't believe they didn't use Y connectors. When I bought the toilet I read the warning, however, I thought it was not going to be a problem.

Thanks

 

[Breplum]

As long as your bowl doesn't empty too much, live with it. I have similar back to back Drakes and I have yet to be sucked down.

 

[Sponsor]

 

[Costa]

As long as your bowl doesn't empty too much, live with it. I have similar back to back Drakes and I have yet to be sucked down.

Hi, thanks - yes, it doesn't empty, and the water raises up again.

 

[WorthFlorida]

From the Toto installation instructions. Is there a vent off the wye if you're connected this way?

 

[Costa]

From the Toto installation instructions. Is there a vent off the wye if you're connected this way?

I don't know. Just bought the house last year. Someone else recommended to check the vent.

 

[Jadnashua]

Modern, low-volume flush toilets either use a siphon jet or pressure assist to maximize their ability to evacuate the waste. So, most all modern toilets can have a problem if the fitting in the wall with back-to-back toilets isn't correct. It's that speed with which it moves the waste that's causing it to skip over into the other bowl. In a worst-case scenario, that other toilet will eventually empty unless it is flushed that will refill it.

 

[Terry]

This video explains what happens on some older plumbing. It's not the venting.
And yes, you can live with it. The bowls will not totally empty, and the more you are even in your use, the more water will remain in the bowls.

 

[Costa]

This video explains what happens on some older plumbing. It's not the venting.
And yes, you can live with it. The bowls will not totally empty, and the more you are even in your use, the more water will remain in the bowls.

Yes, thank you, I've seen your video - the same thing happens in my case. I was worried that the stuff that is supposed to be flushed from the toto goes to the other toilet.

 

[Terry]

In 1979 the double fixture fitting was considered fine with the five gallon toilets of the day. Those had a 2" flush valve and water slowly left the bowl.
Now, all of the new toilets use less water, but do it much quicker. I first noticed this in a home I had with one toilet pulled, the wife flushed a toilet in the adjoining bathroom. Looking down, I saw water coming toward the 90 below the closet flange. Water was skipping across and over to the other drain line for the toilet located in the Master bath. With this home, all of the plumbing was exposed and so it was easy to see that the plumbing was correct for the 80's, and still correct plumbing in todays codes. The codes have not caught up yet with the more modern equipment we all use now. The manufacturers have it in their instructions though as a warning,. Unless you plan on installing some old slow flushing toilets, I would keep the new ones. I have the same issue in my home, and it's not a big deal. They work well, and there is always water in the bowls, just not as high as you might expect. Enough though.

 

[Costa]

Thank you for your feedback!

 

[Costa]

After using it a few days, it turns out stuff travels back to the other toilet . This is not good. I will have to call a plumber.
Just curious, how much would it cost to change the connector roughly and prevent this from happening (assuming it's not a venting problem)? Is it a $1k job, or rather $3-4k? Or should I just be looking at buying another toilet?

 

[Jadnashua]

Most newer toilets tend to rely on a siphon jet or are pressure assisted, so their output will have more velocity than older toilets...so, it's not restricted to just being a new Toto toilet.

How easy it is to resolve the issue, hard to say. Depends somewhat on how wide the studs are (how deep the wall is), and what's beneath. You'll need to patch probably both the walls in the-back-to-back bathrooms, and maybe the ceiling below. If you can repair the stuff other than the plumbing work, you'd probably save a fair amount. Plumbers often aren't the greatest carpenters, plus, their rates may be more than you want.

One of the pros may have a better handle on this in time, but every job is slightly different, so it would only be a guess.