My home is pre-plumbed for a water softener -- whole house water filter. Meaning I have a main water pipe that comes out of the wall, makes a u-turn, and goes back into the wall. Just below the water pipe is a drain point for connecting the softener/filter drain hose. My question is this: The drain point is located 36" above the floor. I am considering installing a utility sink in the garage and I'm wondering if there is a way to utilize this drain point for the sink? Of course the bottom of the sink and p-trap would be considerably lower than the drain point which is up higher on the wall. I do not believe water from the sink would ever drain properly and would most likely just back up in the sink. Would this be the case? Any suggestions on how to get around this?
That isn't how gravity works.
Drains like sinks are typically gravity drains where the water is drawn down into the drainpipe... by gravity.
This is in contrast to things like washing-machines where the wastewater is pumped out into standpipes.
In order to drain your sink via a standpipe above the fixture you'll need a drain pump or drain into a sump and pump it out from there.