Design Goal - I would like to add a Clothes Washer to my basement. The problem is that the only drain available for this purpose in the basement has a 2" horizontal run (beneath the slab) and the state plumbing code requires all clothes washer horizontal runs to be a minimum of 3". The clothes washer standpipe is still specified as 2", but per code the first connecting horizontal run must be 3".

I have a 3" horizontal main drain stack overhead that I can tie into. My plan is to use a gray water ejector pump to handle the flow from the washer and dump it into the 3" overhead soil stack. The ejector pump I'm considering is the Saniflo Sanivite, specifically designed for this application. Per the flow specifications on the washer and the pump given the rise (head) the pump should be able to adequately service the washer at ~23GPM. The ejector pump has a top inlet port with a 2" adapter coupling where I will connect the laundry standpipe 2" drain outlet. I will use 1 1/2" PVC to vent the pump enclosure (per Mfg. specifications) and a separate 2" PVC vent on the washer drain standpipe P-trap.

I would welcome constructive feedback and information on best practices and potential code violations associated with the following drawing. Note... the drawing is not to scale.





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I can't see the picture but it sounds like you have a good idea of what to do.

Thanks North Carolina Plumber. Sorry about the image, hopefully the link to the drawing is fixed now. I'd still welcome any feedback anyone has about this installation, rather than go it alone trial and error wasting the inspectors time a patience.

I would use a Liberty 404 pump instead. I would never use a 1" discharge line for a laundry pump.

Thanks JLNY, I sincerely appreciate your feedback and I agree in spirit. I already have a fairly robust Liberty system serving the shower, toilet, lavatories and major plumbing service for the basement. The issue is the local code requirement to have a 3" horizontal drain line for the washing machine. The goal of this niche system is to install a simple non-basin system (sits on slab) to specifically service the washing machine. There will never be a gravity fed lateral line in this system < 3 inches. I'm suggesting this alternative to the liberty sewage ejector system because the quotation I received to plumb a 3" soil line into my existing liberty system was $$$$. A significant portion of the slab would need to be reworked due to proximity of all the fixtures/plumbing.



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i would run the 1 inch discharge straight up and have just 1 long sweep 90 at the top. less fittings mean less resistance so the pump will work more efficiently.

I added a laundry sink next to the washer and used a Hartell LTA-1-ABC Automatic Direct Mount Laundry Utility Sink Drain Pump that mounts to the bottom of the sink. No vent is required with this set up and is fully code compliant. I have had no issues with a 1" pump discharge, but I am using a lint sock on the end of the washing machine discharge hose to keep debris out of the pump.




I put the washer and dryer on their own 20a circuits with GFCI outlets. I added the outlet for the pump on the "load" side of the washer GFCI, so if the pump ever trips the GFCI for any reason, the washer will shut off also. Off-topic for this forum, but the new NEC removed all exceptions for GFCIs, now required for washing machines.



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