Any sand/grit/sawdust (or other foreign matter) that gets into the pump will cause the pumphead to leak and/or not pump properly. ALL (Sureflo and Flojet) sell (and recommend) using an inlet strainer with their pumps. This is an "optional" OEM device but Keystone doesn't install a strainer on any of their products (that I know of, anyway).
I'd recommend an inlet strainer be used between the fresh water tank and the pump on all installations. It's a $10 device and will save the pump head from "self destruction" should there be sand/grit or sawdust (it's there, trust me) that is either left over from Keystone's manufacturing process or from "gritty water" at a campground.
Don't forget to clean the filter screen during winterizing.
Here's the link to the FloJet strainer. It simply "clips onto the pump and the FW tank hose clips onto the strainer (just like it did to the pump). No alterations and no modifications required.
https://www.amazon.com/Flojet-017403...+pump+strainer