good day all,

Here's the situation -

I am building a darkroom that has access to water coming in, but not
going out.

It is going to be in the middle of my garage - not sharing any walls with the outside. On top of that, there are no drains in the garage.

So, my thought is to put a sizeable holding tank under the sink. In the tank
will be a sump pump that will pump the water up and out, via a hose or pipes, to a point where I can connect with the house drain system.

The least invasive/destructive route would involve pumping up to the garage attic and across to an adjoining room, then down to a drain for our clothes washer.

Anyon out there have a rube goldbergian setup like this?