Can I use just water for Easy Wash Sunscreen?

The children's version is gentle, so I use it often too.

My child uses it, and I use it too...

Sunsticks are a case in point, too...

Since I am an adult, I usually double cleanse.

Most children wash their faces with just water...

Very occasionally, I also wash my face with a very mild cleanser.

I saw they had Easy Wash sunscreen...

I wonder if it would be okay to just wash my face with water for something like this...

I'm curious...