Ice Maker Drain

Just bought an Ice Maker and want to fit it in the garage on a wall that backs onto a half bathroom (Dry Wall) I know I can cut the dry wall and tap in to the water delivery no problem but can I run the drain from the ice maker to a low point on the sink drain (Below the U bend?) Would I need a one way check valve? Any help appreciated.

No.................!

You would need an air gap to prevent the possibility that a backup might pollute all of your ice with sewage.

my non-professional opinion

My non-professional opinion is that the drain is going to go into an air gap and then join the tailpiece of the sink drain above the trap. Like a dishwasher drain.

You cannot make a connection below a trap. You cannot allow possible cross connection of a machine...icemaker, dishwasher, etc. with a backed up drain, and a check valve does not meet code for this protection.

So an air gap, such as is used for dishwashers and RO filters, or a standpipe, such as is used for washing machines. If your ice machine has a pumped drain, this is easy. If it is a gravity drain, it is back to the drawing board!

And for most icemakers there is a pump version or a pump as an option.