The splash ones are water resistant.
They have a stall at the equine event over this weekend. It's the stand with the jods with hosepipes running water down them
i just nikwax mine! it lasts for ages and it doesn't alter the appearance of the clothes at all-i do all my winter stuff at the beginning of the wet season and don't have to proof em again
it's nice and cheap too,i use cotton proof on my jods and fleece proof on my tops.
loveson do a nice water resistant jod called aqua-but from what i remember they're really lightweight