Or maybe he just has cleaner water in his toilet? 
Have you thought about that?
aaaaaaaaa… I’m gonna go out on a limb here…
Fog?
Aaaaaaa, sorry… but I still think you chose the weirdest metaphor ever… Initially I thought you have a problem with the way water looks 
In any case… are you playing on PC? cuz if so… and it really bothers you… you can just do it yourself… A lot of aspects of fog and lighting and colors and stuff can be customized in the UE4 ini files, here’s an example I posted not long ago
Probably try tweaking these for starters
r.Fog=1
r.FogDensity=0.03
r.FogStartDistance=4