# Low flow toilets and sewer slopes.



## Pdesign (Mar 5, 2009)

First: I want to apologize for not logging in as much.
Secondly: I would like to find out if anyone has ever had to change the slope in a sewer pipe to accommodate low flow toilets? 
Preferably in Virginia or North Carolina area.
Thank you.


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## curtis2kul (Sep 14, 2008)

Still 1/8th per foot here in North Carolina.


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## gitnerdun (Nov 5, 2008)

Who suggested you do this?


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## Pdesign (Mar 5, 2009)

gitnerdun said:


> Who suggested you do this?


I am a designer and I am just trying to find out if anyone has ever had to change the slope because of the low flow toilets. 
I have read that it doesn't carry the waste as far as a 3.5 gallon talk would. One of our clients seem to have an issue with a main line clogging about 30 ft down from where the toilets are located. They say the slope is 10 inches lower from one clean out to the other in a 65 ft length. There is a low spot where new piping connects to existing piping and that is what we believe is causing an issue but the clients and a few others believe it's the toilets.


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## Plumber (Jan 18, 2009)

Pdesign said:


> I am a designer and I am just trying to find out if anyone has ever had to change the slope because of the low flow toilets.
> I have read that it doesn't carry the waste as far as a 3.5 gallon talk would. One of our clients seem to have an issue with a main line clogging about 30 ft down from where the toilets are located. They say the slope is 10 inches lower from one clean out to the other in a 65 ft length. There is a low spot where new piping connects to existing piping and that is what we believe is causing an issue but the clients and a few others believe it's the toilets.


It's an issue, but not well documented yet. 

I would make darn sure that the toilet is the last fixture on the branch. The shower, basin, sink, washer, etc. will help wash the waste down the pipe.


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## Redwood (Sep 8, 2008)

A long run with shallow pitch can be problematic...
A low spot or, belly in the line can be a big problem.

As for the minimum pitch you have to be more specific with the location to determine the local code used. I believe Virginia has several different codes in use depending on the location, nevermind adding in North Carolina as well...

I'd recommend a video camera inspection of the line.


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## Pdesign (Mar 5, 2009)

Plumber said:


> It's an issue, but not well documented yet.
> 
> I would make darn sure that the toilet is the last fixture on the branch. The shower, basin, sink, washer, etc. will help wash the waste down the pipe.


Thanks..they are on the last of the branch. The showers and lavatories are before the water closets. There is a washing machine and other things way before them also.


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## Pdesign (Mar 5, 2009)

Redwood said:


> A long run with shallow pitch can be problematic...
> A low spot or, belly in the line can be a big problem.
> 
> As for the minimum pitch you have to be more specific with the location to determine the local code used. I believe Virginia has several different codes in use depending on the location, nevermind adding in North Carolina as well...
> ...


We believe the small low spot/belly is the problem and they even did a camera inspection with out recording. They will be doing the camera again with recording this time. I have already read the minimums for Virginia and North Carolina but I have not spoke to inspections or anyone of that nature yet to see if they recommend a larger slope for low flow toilets. They are trying everything they can to see if it's something else other than the small low spot/belly that is at the end of the line outside where the new connects the old. They really don't want to tear up that area.


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## plumber666 (Sep 19, 2010)

I'm working on a school addition right now, and first time I saw the prints, I noticed all sanitary lines, including 4" were spec'd at 1/4" per foot. I asked the engineer why that was and he said it was because of the low flow toilets, and that they needed the steeper grade because there was less water. 
When I said I totally disagreed with him, as there was a greater likelyhood of the solid and liquid wastes separating with more grade, he gave me a "deer in the headlights" look. Said the steeper pitch was a new policy for them, but would look into it. That was about 6 months ago, I should really give him a call again.
What's everybody elses opinion?


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## easttexasplumb (Oct 13, 2010)

Use min pipe sizes and slope, to help the water carry the waste.


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## Plumber3653 (May 5, 2010)

Sometimes it is the connection of the new pipe to the old pipe that catches debris that would normally pass the transition without issue. I would follow Redwoods advice. Any bellies or shifted connections or bad transitions should be addressed.
IMO slope is not an issue when it comes to low water consumption toilets as long as the minimum grade is made. My sewer has never backed up and it's a 50 year old clay with about 1/8" of fall to it. (Yes, I inspected my sewer and timed the flow between two points. Future basement bathroom to be installed at later date.)


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## Greenguy (Jan 22, 2011)

My last company did a retrofit on an old 150 year building, they had 4 washrooms in the basement that drained 30' to a sump, the pipe grade was 1/4" per foot as is code out here. Within the first two weeks they had a few floods. They found that people were trying to flush paper after pushing the pee button. Has the toilet rep came out first thing he asks is what's the grade on the pipes then he tells us it has to be 1/3" per foot minimum. 

For the life if me I can't remember what brand they were.


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## CaptainBob (Jan 3, 2011)

We did a remodel in an old commercial building a few years ago, installed new 1.6 gal flush toilets. A week or two after the final and the clients started using the building the lines started getting plugged up. The contractor got them snaked out, thinking maybe there was some debris in the lines from before the remodel. Again, a couple weeks later, lines were plugging up. They called us back to get it figured out, we ended up installing used 3.5 gal flush toilets to solve the problem. It didn't make the contractor look good to his clients, lost doing any more business with them over that.  government liberals and their low flow toilets.:furious:


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## Protech (Sep 22, 2008)

I would focus on keeping the hydraulic diameter smaller so as to increase velocity.

The only problems I have run into were long, large diameter drains with little pitch and few branch connections within close proximity of the toilet.


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## Bayside500 (May 16, 2009)

CaptainBob said:


> We did a remodel in an old commercial building a few years ago, installed new 1.6 gal flush toilets. A week or two after the final and the clients started using the building the lines started getting plugged up. The contractor got them snaked out, thinking maybe there was some debris in the lines from before the remodel. Again, a couple weeks later, lines were plugging up. They called us back to get it figured out, we ended up installing used 3.5 gal flush toilets to solve the problem It didn't make the contractor look good to his clients, lost doing any more business with them over that.  government liberals and their low flow toilets.:furious:


is that even legal ?


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## CaptainBob (Jan 3, 2011)

Bayside- No it isn't, we changed them out long after it the final inspections...:whistling2:

Protech- You can only go so small when you have to follow what the code says what diameter pipe you have to use for so many fixtures...


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## Protech (Sep 22, 2008)

I have never had any problems with a QUALITY 1.6 toilet installed on a 3" line with 1/8" slope and other fixtures tied in near by.

You sure you don't have a back-pitch in there somewhere? :whistling2:



CaptainBob said:


> Bayside- No it isn't, we changed them out long after it the final inspections...:whistling2:
> 
> Protech- You can only go so small when you have to follow what the code says what diameter pipe you have to use for so many fixtures...


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## Redwood (Sep 8, 2008)

CaptainBob said:


> We did a remodel in an old commercial building a few years ago, installed new 1.6 gal flush toilets. A week or two after the final and the clients started using the building the lines started getting plugged up. The contractor got them snaked out, thinking maybe there was some debris in the lines from before the remodel. Again, a couple weeks later, lines were plugging up. They called us back to get it figured out, we ended up installing used 3.5 gal flush toilets to solve the problem. It didn't make the contractor look good to his clients, lost doing any more business with them over that.  government liberals and their low flow toilets.:furious:


So you broke the law and hid the problem rather than fixing anything... :thumbup:

I'm Impressed.... :no:


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## CaptainBob (Jan 3, 2011)

Well, it was the simplest and cheapest way to solve the problem...I had a feeling there was some backpitch or bellying involved, but with payment for the job being held over our head, and the clients not wanting to tear the building apart to fix it, that was the solution...If we went to the AA over it, they probably would have granted us a variance to install those toilets anyway, knowing how they were in that city...


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## Redwood (Sep 8, 2008)

CaptainBob said:


> Well, it was the simplest and cheapest way to solve the problem..*.I had a feeling there was some backpitch or bellying involved,* but with payment for the job being held over our head, and the clients not wanting to tear the building apart to fix it, that was the solution...If we went to the AA over it, they probably would have granted us a variance to install those toilets anyway, knowing how they were in that city...


So you didn't cam and locate the line to check it before the remodel work...

And now the customer has a remodeled bath with a 15 year old used toilet in it...:blink:

I'd be thrilled, and you'd be trying to get paid, while I showed you the door if it was my place....:yes:


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## 504Plumber (Jan 26, 2011)

Why not install pressure assist toilets instead of some old junk?


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## nhmaster3015 (Aug 5, 2008)

I wonder how well a toilet would flush on a 2" line? I think it's time for another test :thumbsup:


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## U666A (Dec 11, 2010)

nhmaster3015 said:


> I wonder how well a toilet would flush on a 2" line? I think it's time for another test :thumbsup:



You should change your log in to "Bill Nye, the Plumber Guy"... Y'all remember that show?

I guess you have all the resources available to you to perform all these crazy experiments eh NH?

Ever try setting them up with Kimax? At Mohawk, where I attended trade school, they had a sophisticated plumbing system set up on a wall all piped with Kimax. They also had pneumatic solenoids on all of the vent pipes so you could physically see how a w/c could pull the trap of a lav. They didn't however, have any 3" x 2" bushings jammed into the closet flanges... :laughing:

Let's see!

Sent from my iPhone using PlumbingZone


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## nhmaster3015 (Aug 5, 2008)

Yep, gonna do it tomorrow. I'm curious myself. I suspect that the toilet will flush just fine. Should do a whole series "Plumbing MythBusters" :laughing:


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## Redwood (Sep 8, 2008)

504Plumber said:


> Why not install pressure assist toilets instead of some old junk?


Pressure Assisted Toilets are not always a cure all for bad plumbing...

I went on a call at a supermarket where they were having a geyser erupt out of a floor drain and the lav sink whenever the pressure assisted toilet was flushed. Snaking the line had not helped the problem. A camera inspection revealed a back pitched section of the pipe that also included a 1/4 bend in it.

The high pressure short duration flush hitting that resistance in the line was causing the geyser to erupt out of the floor drain and lav sink.

Rather than search for bandaids to mask a problem it is almost always better to fix the actual problem as it will give the customer a properly functioning drain and it will keep your company's good reputation intact.:yes:

If the customer will not approve the proper repair then it is time to walk away fron the job rather than let the customer tell you how to do your work. We all know that when the customer's brilliant idea doesn't work who will be at fault.:yes:



nhmaster3015 said:


> Yep, gonna do it tomorrow. I'm curious myself. I suspect that the toilet will flush just fine. Should do a whole series "Plumbing MythBusters" :laughing:


Considering the size of the outlet horn on toilets I suspect it will as well.

Now if you throw a 90 degree pressure el into the mix I can see a problem with solids passing.:laughing:

At least those ones that jam up in the dog leg on the Kohler Wellworths...


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## nhmaster3015 (Aug 5, 2008)

I have had a suspicion for awhile now that pretty soon the code will be ammended to allow a 2" toilet line with limitations for distance and fittings.


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## Lifer (Nov 23, 2010)

Last week two of the guys from the shop went on a plugged main line call ... On a Scallop Draggier ( fishing ship , Large ) When they got there they were surprised to find the rooms each have there own full bath which 2 men shared and in total there were more than 30 toilets... they were on a 2" ( metric though Scandinavian ship ) Vacuum line for all of the drainage , yea i know it's a vent thread but there were no vent's there at all .. kinda different . They actually ended up cutting the line in a few places to clear the clog and the pipe was a brass or copper type of pipe .. ( they had never seen this type before ) Turns out toilets will flush just fine on a 2" line but ... Paper towels still will not .. lol 


Lifer...


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## SewerRatz (Apr 25, 2009)

Pressure assist water closets are worse. They stretch the flush out longer so the slug of water does not wet as much of the pipe. The newer water closets with the over sized flappers are much better for caring the waste down stream. They have a quick short flush which makes for a slug shorter slug of water that wets more area of the pipe.

As for using 3.5 gallon per flush water closets, I was always told they are allowed for commercial use only. The ones my supply house carries are stamped with just that "For Commercial Use Only" .


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## Redwood (Sep 8, 2008)

SewerRatz said:


> Pressure assist water closets are worse. They stretch the flush out longer so the slug of water does not wet as much of the pipe. The newer water closets with the over sized flappers are much better for caring the waste down stream. They have a quick short flush which makes for a slug shorter slug of water that wets more area of the pipe.


:blink:
Are you sure you have that right?


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## CaptainBob (Jan 3, 2011)

504Plumber said:


> Why not install pressure assist toilets instead of some old junk?


We discussed using pressure flush toilets. The customer didn't want to pay for them. In fact, they didn't want to pay for anything more than our original bid. If I remember right they asked us if we could put the original toilets back in after all that. Unfortunately, they ended up in the dumpster.

Like others mention here, we were doubtful they would help, anyway.

Bottom line is, we got it working, we got paid, clients were happy. The contractor wasn't, because it made him look bad that there was a callback like this.

A lot of you guys know as well as I do anything above and beyond the original bid is like pulling teeth trying to get paid on. This job, like many, was bid pretty tight. And the clients didn't want to tear apart any other part of the building with the additional costs. And, especially when it worked fine before we put in 1.6 gal toilets. It seems that there are a few of you here that (gasp) seem to be upset we installed more than a 1.6 gal toilet.

Red- If you recall, the contractor showed our shop the door after this project. They would have showed it to you just as fast.


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## CaptainBob (Jan 3, 2011)

nhmaster3015 said:


> I wonder how well a toilet would flush on a 2" line? I think it's time for another test :thumbsup:


I worked on a remodel job a few years ago where the DIY homeowner ran a toilet into a 2" line.

It had a 3" flange, 3" pvc for a few feet then reduced down to 2" pvc, ran a few more feet, then dropped vertically down into 2" cast iron under the floor.

If I remember it had a 1 1/2" vent on it that the lav was wet vented into.

It was an inexpensive 1.6 gal flush toilet, and it worked just fine.


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## U666A (Dec 11, 2010)

Lifer said:


> Last week two of the guys from the shop went on a plugged main line call ... On a Scallop Draggier ( fishing ship , Large ) When they got there they were surprised to find the rooms each have there own full bath which 2 men shared and in total there were more than 30 toilets... they were on a 2" ( metric though Scandinavian ship ) Vacuum line for all of the drainage , yea i know it's a vent thread but there were no vent's there at all .. kinda different . They actually ended up cutting the line in a few places to clear the clog and the pipe was a brass or copper type of pipe .. ( they had never seen this type before ) Turns out toilets will flush just fine on a 2" line but ... Paper towels still will not .. lol
> 
> Lifer...


Have seen something similar to this working at the local dry dock. All piping aboard is like a sched 80 bronze material. Like you said Lifer, all 2"

Sent from my iPhone using PlumbingZone


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## Redwood (Sep 8, 2008)

CaptainBob said:


> Red- If you recall, the contractor showed our shop the door after this project. They would have showed it to you just as fast.


We would have probably shown the contractor the taillights long before that point.:laughing:

There are a lot of jobs that we refuse to bid on...


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## SewerRatz (Apr 25, 2009)

Red I am positive, the power assisted water closets have a longer flush to cleanse the bowl, where the Class 5 and better water closets just move the water out in a quick short flush. 

I have proven this by replacing many pressure assisted water closets in stores, that had constant back ups. Once I put in the gravity flush water closets I have yet to get a call from them about a back up.


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## 504Plumber (Jan 26, 2011)

SewerRatz said:


> Red I am positive, the power assisted water closets have a longer flush to cleanse the bowl, where the Class 5 and better water closets just move the water out in a quick short flush.
> 
> I have proven this by replacing many pressure assisted water closets in stores, that had constant back ups. Once I put in the gravity flush water closets I have yet to get a call from them about a back up.


Wouldn't a longer flush in turn flush more water through the sewer?

I only brought up pressure assist because of what the OP said about having to put in an old toilet. Are there any laws out west that prevent pressure assist being put in due to higher water volumes?


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## Redwood (Sep 8, 2008)

The volume of water used per flush is the same.

However the flushmate sends it in 3 seconds vs. gravity in about 9 seconds.

After which the flow tapers off and bowl refilling occurs.


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## rollsdownhill (Jul 17, 2012)

*ultra low flow fixtures*

I agree with minimum slope. I would also agree to try and keep the low flow fixtures "down stream" of other fixtures to help wash the lines with showers/tubs, lavs etc. The problems I am seeing is with retro fit applications. Especially when there are existing cast iron pipes and little or no other fixtures up stream to wash the line.

I know this is an old discussion. I just joined the forum today,,, Has anyone learned anything since?


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## PinkPlumber (May 20, 2012)

rollsdownhill said:


> I agree with minimum slope. I would also agree to try and keep the low flow fixtures "down stream" of other fixtures to help wash the lines with showers/tubs, lavs etc. The problems I am seeing is with retro fit applications. Especially when there are existing cast iron pipes and little or no other fixtures up stream to wash the line.
> 
> I know this is an old discussion. I just joined the forum today,,, Has anyone learned anything since?


:whistling2:
:shuriken:
:hammer:


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## Protech (Sep 22, 2008)

I have seen quite a few problems with oversized drains on low flow toilets. 4" drain serving nothing but a toilet and a lav for a 60' run = bad news


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