Using PEX for backwash drain

I don’t see why you couldn’t. Downfall of PEX (IMO) would be inability to really set a proper slope in the line, so you’ll end up with some residual water in the line. Rolled PEX can be a bear to wrestle into a trench and try to keep in any sort of controlled position. I ran a water line to my shop with PEX and it’s been fine.

wrassiling 30’ of pex from a roll will be a PIA but you can get 10’ or 20’ sticks and join together with a coupling

PVC is about as easy as it gets so I'm not sure i agree with you. You'll need PEX crimpers if you don't have some already vs a $6 can of glue and $4 can of primer. PVC will hold the grade better than PEX. PVC is 200x more UV resistant than PEX so if any of it will be in sun light PVC seems like a no brainer.

Thanks for all the input. I'm pretty ignorant when it comes to PEX so I'll just go with PVC.

Another question. What do y'all think would be the best way to set up the tail end of the drain line? I've done french drains before, but it doesn't look like they make a 1" popup emitter or something like that. I was thinking about just putting a 90 degree elbow on the tail end and then putting some screen or something on the top of it so it doesn't get clogged. I don't know if there's any way to avoid some standing water in the drain, but also don't know that it matters that much since it's a forced drain.

It’s a 28 gallon filter. Not sure how much water it holds when factoring the filter media but it backwashes twice a week and it’s not a ton of water. It’s just backwashing straight into an area of my yard that stays damp during the winter because of lack of sunlight so it’s enough to turn something that’s not a huge deal to me into a problem, if that makes sense.

It’s one of these:

LINK