I know in Florida we do not dig deep to bury pipes. I think today's code for supply lines is 18" not sure what it is for drains. We don't need to worry about freezing.

This is a rental property and I have been contemplating a project to connect my 2" laundry drain to my 2" kitchen drain. Finally the tenant moves out so I can do this.

Presently, my laundry machine is in a shed next to the car port, the 2" line runs outside and drains into a gravel pit, not connected to the sewer line. That water attracts termites. I would like to connect to the city sewer.

I also know about 22' away, I have a kitchen drain (1955 original construction, CI line) that exits the house and ties into the 3" main line somewhere. My plan is to find the 2" kitchen drain where it exits the house, runs the 2" laundry line there and tie the two together.

So I lifted off the large patio stones off the sides of the house where I expect the kitchen drain to exit. I found the pipe immediately. No excavation needed. It's right under the patio stones.





It's a bit shallower then I had expected. It may be like 1/2" under the patio stones.

This presents a challenge because I was hoping to run the 22' line from the laundry shed to this line below grade. If this pipe is so shallow, to keep a 1/4" per foot slope I need a tad over 5" of drop. I do not have this much drop.

If I start high on the upstream I run the risk of the top of the pipe actually be at grade. Bad for lawn mowers, wheel barrows or whatever that may roll across and break it.

Unless I can go to 1/8" per foot or even less?

Or I can lift more stones downstream and see if it goes deeper somewhere?

Thoughts?



Edited 2 times.

You might have to install a laundry tray and pump system in order to meet code.

Although I do think if you ran your drain flat or with very minimal grade it would work just fine.

Maybe do a yearly cabling just to make it sure it stays clear and problem free.

Approx how many feet is this point from the center of the street? It’s gotta drop deep at some point to connect to the city sewer right?

"Approx how many feet is this point from the center of the street? It’s gotta drop deep at some point to connect to the city sewer right?"

Yes. But this is in the back yard. The pipe used to run to the old septic tank which was abandoned in 2008. So this 2" pipe runs another 24' before it ties into a 4" PVC sewer pipe, the 4" runs about 120' before it crosses the property line out front, and another 25' to the street.

Of course I am trying to avoid chasing this further and further to find a deeper tie in point.

Here are more pictures and illustrations.

This shows the CI kitchen drain to the left, and the PVC laundry drain (to the right).



The idea is to run the laundry line over below grade. The distance between the two is about 22'.



The first surprise is the depth of the kitchen drain.

The second surprise is while I was digging and cutting the trench, I found yet another CI pipe 6' to the right of the kitchen drain. This mystery pipe is also a 2" CI pipe, exits at the same elevation and transitions to a 3" after a short section.



I opened all the faucets and flushed toilets and I do not feel any water running past this mystery pipe. I am thinking this may have been the original kitchen drain, then at a later date they moved it? To me it seems like an abandoned pipe, there is nothing on that side of the house that drains except the kitchen. The vent on the roof lines up with the drain pipe to the left.



In any event, this pipe is in the way of my proposed PVC drain. So I will have to cut through it anyways.



Originally I was thinking just a WYE on the 2" CI as soon as it exits to tie in the new PVC. However thinking about it a bit more, if I go a bit more downstream I gain another inch of drop. May be I will do this instead.

Does this mystery CI pipe look much older?

2" CI KITCHEN DRAIN:



2" CI MYSTERY DRAIN:



I have always wondered why they would have a hot and cold hosebib connection in the back. Now when I look at the mystery CI pipe and the hot/cold hose bibs, I am guessing those used to be the kitchen faucet connections that were turned to the exterior when they did the renovation.



Any old timer plumbers here that recognize this CI elbow? It says "2CFCO" (not sure) on the hub. On the elbow it says "H" and "5LBS". May be I can determine the age of this fitting. If it's much later than the original construction date then this drain was definitely added later when the other one was abandoned.





Edited 1 times.

sum, if the mystery pipe does happen to be alive. it doesn't have much life left.
i would guess it is abandoned.
if your concern is that the proposed new laundry drain will be damaged, run it in cast iron.
you can probably rent some soil pipe cutters.

Sum looking again at your pic that shows your proposed routing as a red line around the corner...

Does the pipe really need to be buried the whole way? I’m trying to think how high off the floor the trap wier must be... but say it’s like 6” off the floor, could you just come thru the wall, then have the pipe strapped to the outside wall rather than being underground? And then turn it down and join the kitchen pipe nearby to where it exits the house?

Also, can you run that pipe on the inside of the wall instead of outside? I know you mentioned that’s a kitchen and perhaps a garage next to it... but maybe if you could run it inside behind a cabinet or something it would save you some drop & distance?

"Does the pipe really need to be buried the whole way?"

Ideally yes. I would prefer not to have a pipe sticking up partially above the ground.

"I’m trying to think how high off the floor the trap wier must be... but say it’s like 6” off the floor, could you just come thru the wall, then have the pipe strapped to the outside wall rather than being underground? And then turn it down and join the kitchen pipe nearby to where it exits the house?"

Yes I can, but I'd rather not to. The trap wier is not a constraint. This is downstream of the vent. Note that this is going around a building corner. A 2" elbow will NOT allow you to have the pipe hug the wall, but will have to stand off the wall some distance. It will be a real eye sore.

"Also, can you run that pipe on the inside of the wall instead of outside? I know you mentioned that’s a kitchen and perhaps a garage next to it... but maybe if you could run it inside behind a cabinet or something it would save you some drop & distance?"

It will be a lot of demolition, involving breaking through an 8" concrete wall, into and through multiple kitchen cabinets, then out another 8" concrete wall again. Just not enough pluses against the minuses.

If you look closer at this picture previously posted, on the right side is the laundry line. It's already outside, and it's already on the exterior wall.

"sum, if the mystery pipe does happen to be alive. it doesn't have much life left.
i would guess it is abandoned."

I am pretty sure it's abandoned, but I am going to make a cut through it first, and run everything in the house to make sure nothing comes out of it to make absolutely sure. Being that it's a 2" line, the only thing I can think of it's an old kitchen drain being abandoned, or it could be an old laundry line (it does seem in line with the laundry machine on the other side) that was abandoned due to collapse or whatever. Which could explain why they made a new PVC laundry drain and drained the water into a gravel pit outside.

"if your concern is that the proposed new laundry drain will be damaged, run it in cast iron.
you can probably rent some soil pipe cutters."

Yes I might think about this, CI is much stronger and if I lay it down it won't be damaged. I don't think I need to make a lot of cuts can probably get by with a reciprocating saw with a thick metal blade. I would need to do all no hub connections, I can't pour lead joints nor do I want to mess with rubber donuts besides the hub makes it even higher off the ground.

“The trap wier is not a constraint...”

Sorry let me clarify, I wasn’t referring to venting. I was referring to the height requirements of a washing machine drain. Too high and you have pump issues, too low and the machine won’t hold water. (At lease some models I’ve seen).

I think you need a 24” standpipe, and the top of the standpipe is supposed to be around the height of the washer lid. An expert here could provide the details as I’m not sure. But then you can work backwards to the maximum height of your trap above the ground. The higher it is, the longer your run could maintain 1/4” per foot drop.

Of course, if you want it totally buried outside, this is all rather moot.

Unless you do this then build a raised planter or something over that portion of the pipe. Call it an herb garden.

Palm329, I understand but I have no constraint plumbing wise on the upstream side. I already have a 24" stand pipe, and below the sanitary tee branch I have over 18" of play before I reach ground.

The constraint is the downstream tie in point being too high and yes I do not wish the pipe to be exposed above ground and wrap around the building. There is no plumbing constraint at the upstream end.

If I start the top of the pipe at grade upstream, then gradually slopes down to the kitchen line which is less than 2" below grade, we are talking about 1.5/16" per foot. Very flat.

If I start the bottom of the pipe at grade then gradually slopes down to the kitchen line, then I have about a 1.6/8" per foot. Better. But then a length of pipe will be partially exposed.

If the drain services the washer only (ie no laundry sink) then you will only have liquid discharge in that pipe, no solids. A 3/32 slope is shallow for sure, but with just laundry suds it should be OK and not in danger of clogging.

- - - - - - -

Not a plumber by trade but a fierce DIYer

I was taking a look at the old mystery apparently abandoned 2" CI line again. It didn't transition to 3". That was just a really fat looking coupling? I thought it went to 3" because the coupling seems much bigger, I guess either it was a really thick coupling, or the corrosion over the years made the CI swell up like this?

OK I think I may have a strategy here. I traced a level line along the wall horizontally around the corner from the kitchen drain to the laundry line.

I found the top of the ground at the laundry line to be 1" higher than the top of the 2" kitchen drain. So if I put an elbow such that the top of the pipe is flushed with the ground, I only have a 1" drop by the time it meets the kitchen drain 22' downstream. That's just too flat I think. It will work but I like to give it a bit more slope.

So I did some additional measurements.



I measured the vertical distance from the top of these paver tiles to where the kitchen drain goes under the tiles. It's 3.5" down.

I then went to the other side of all these tiles and started digging for where the kitchen drain emerges again, 10' away, and found it to be 11" down.



so 3.5" below to 11" below over a distance of 10', that's a slope of 6%. Now if I lift up another two of these 24" tiles and dig down, and make the connection there instead, at 6% slope I would gain another 3" of depth, add that to the 1" I started with, I will end up with 4" of drop over 26'. That's 1.5% slope, about half way between 1/8" and 1/4" per foot. I think I might have to settle for that.



It also means the kitchen line has to make the tie further down, with a wye slightly rolled up since the laundry line may be slightly lower than the existing kitchen line when it run past it. So something like this?



Now, the only problem I have is since that 2" CI line is at a 6% slope, and I need it to come out at 1.5%, how would that work? Do I:

( A ) "cock" the 2" PVC pipe to make it conform to my desired slope since I will be using a banded 2" CIXPVC transition coupling? 2" may not bend like the smaller PVC pipes.

( B ) Use a 22.5 degree elbow, row it this way and that until I get to the slope I want...but then again, once I do that, it may point in a wrong direction and I need to follow that path I have exposed.

( C ) Custom make a length of 2" PVC pipe that turns 4.5 degrees with a heat gun.

( D ) Something else? What other options do I have?



Edited 1 times.