Will this new drain work for my washing machine?

[ThisGuy]

Hello, I am in florida. I am trying to move the washing machine from the kitchen to the garage, there is no other way to run the drain other than to create a separate drain tank from the septic, im trying to avoid doing that. I want to just run a long drain pipe and tap into the existing washer drain. The problem is, it will have to go up straight vertically when it reaches the original drain pipe, you'll see in the picture. this I think will just create standing water, but still work.. Will this work? if not, why? and can I just add something to the system? or is this just a big no no?

the link below is a diagram of what im trying to do.

https://ibb.co/QCxPmDD

 

[Diehard]

I realize that it's just a crude sketch but I must ask, why doesn't the right(new) p-trap and vent look like the left?

On the left(existing) piping, where is the septic tank relative to the vertical waste line from the washer? How deep is that vertical line before it 90's to the horizontal? Is there not enough room to tie the new line into that line at a much lower level? I assume your septic tank is not below your house.

Without getting into it not being a legal arrangement, what you propose would always be full of water(as you noted), so it will never run as a gravity system. It would run as a force main with the head of water from the new washer standpipe acting as the pressure to push it.
Now although once it's moving through a 3" line it would take very little pressure to keep it moving at a flow required by the washer. The problem is I don't know how much head pressure and time it would take to start it moving, which would relate to how far that washer flow would have to back up the standpipe first.

If you don't have the difference in elevation to make it work by gravity, you could consider a pumped system, with a much smaller discharge line to the point you show on your sketch. (There are a few different options you could look into for pumped systems.)

 

[Jeff Handy]

You should post pics of everything.
Existing location plumbing.
Many pics of the whole route between house and garage.
Pics of the new proposed location in garage, inside and also the outside wall behind it.

I think you will be happier with a laundry tray pump system.
Google it.
As long as the pipe between the buildings won’t freeze, with climate change Fla is getting more severe cold snaps now.

Or create a new tap into the existing drain to septic at a lower level as Diehard mentioned, so it can drain by gravity.
If it can’t be done, explain why with your pics.

 

[ThisGuy]

I realize that it's just a crude sketch but I must ask, why doesn't the right(new) p-trap and vent look like the left?
** because its a crude sketch, the new can be made exactly like the original

On the left(existing) piping, where is the septic tank relative to the vertical waste line from the washer?
** the point where the vertical pipe goes down is in the wall adjacent to master bath, then masterbedroom, then side of house is septic tank

How deep is that vertical line before it 90's to the horizontal?
** I cant tell because it goes thru the concrete foundation, but the main 4inch pipe that goes from ouse to septice is only like 8inchs deep (measuring to the top of the pipe) also the yard is raised where the tank is, so getting to the back yard (which is where id trench the new line) is like 8 inches lower.. so It cant slope

that's why I want to do the verticle rise, the rise would be like 10 inches, and I could tap into the trap part that's in the wall above the foundation

I guess ill look into the pump thing

 

[Jeff Handy]

Maybe you could run an elevated drain between buildings.
Resting on blocks, or clamped to a wood frame like a bridge.
Not very elegant, but then you could still drain by gravity.

Maybe you can put in a dry well off the garage, and just dump your wash water into that?
Or even just dump into a garden or planting bed?
Check local codes.