Injen makes a splash shield that perhaps would work somewhat... But NOTHING will protect from submerging it in water.
Like I put in another post... I believe by you, I drove through snow with my Injen and had NO problems whatsoever. Now your being more cautious than I am, but I have seen how 'covered" the filter is and it's pretty safe unless you go plowing through a puddle that happens to go through the fog light area. That is the most suseptible(sp?) area to soak your filter.