I have to agree with rickymaveety. Fix the textures on the houses and/or tweak the lighting. You have lovely terrain work here; it would a pity to hide it with mist. But if you still want mist, why not try a volumetric slab? Some of the pre-set volume materials are quite convincing. Here's a screen shot of a volumetric slab combined with a water plain. Good luck on the challenge!