Washer Drainage in Basement

Hello,
Looking for a little advice. The wife is looking for projects for me to complete before we have our first child. She wants to move my washer and dryer to the basement in order to build a extra bathroom upstairs. I currently have a 4" Cast Iron sewer line that runs about 4.5 ft above the floor into a Septic Tank. I was adviced with the current set up to just cut a big chunk of the pipe out and start from scratch. I have been reading alot and have seen many different opinions and opinions to do this. Some people have set up a drainage, some have installed pumps. I wanted to get some opinions and possible sketch ideas from others. I have a picture of the current setup.



My plan would be to set up one Wye for the upstairs bathroom and cap it for now (Thats another project for another time). Then possibly put a sideways Wye with a Combo Connector one for Vent and another for P Trap and about 20" Pipe for the washer hose to pump into Example below. Also Something similar someone did. Would this work? Thanks for the advice.

How high is that 4" cast off the floor.

Its 4.5 feet off the floor

It should work, but just be aware that if the main line were to get plugged for any reason the water will overflow out of that "stack" and flood the basement. There can also be issues with "positive pressure" caused by water draining down from the upper level which that AAV cannot relieve.

If you are planning to follow the proper permit and inspection procedure, you should find out what the plumbing code allows where you live. Here, our code specifies that a washer standpipe cannot terminate higher that 48" from the floor.

Setting that aside, installing a pump system would circumvent the increased likelihood of a sewer backup into the basement also. While in most cases I would prefer a gravity drain, this would not be one of them.

I'm still confused on your plans. Is it similar to this photo?

Gee, I hope not. There is no vent on Hammerlines photo.

Terry said:

Gee, I hope not. There is no vent on Hammerlines photo.

Click to expand...

Yeah I didnt edit in a Wye near the bandstrap with an AAV out of the branch

That's better.

Yeah that's is the setup. I just had the Wye coming out of the main drain sideways. To cut down on the overall height. Not sure if that is good to do.
This sewer back up make me nervous though. Would it be possible to put in a check valve somewhere to prevent that. I don't see where that could go though.

So i guess its either use the gravity and risk the backup or go with a basement pump. With the pump, is it true i don't have to worry about a check valve, backup, trap, or vent (if i get the right pump)? That maybe the easiest way to go and save the most space. Maybe even add a slop sink also, and price wont be that much different. I saw some pumps for $200.
For someone who has very really done plumbing projects, I'm learning a lot on this site Terry. Thanks.

If you have the washer drain into a slop sink, then you could get by with a small sink basin and pump that uses 1-1/2" inlet and outlet.

If you are going to use a standpipe for the washer, you will need a more substantial pump and basin system with 2" inlet and outlet.

A pump basin still needs a vent and a check valve.

with that cast iron 54" above the ground and with the normal standpipe height of 30" above the trap weir and not to mention any height the wyes add you are looking at one hell of a upchuck for that washer. Best check the manual for the washer and make sure it has the capacity to overcome all the head pressure.

Do post final photos.