The usual answer is it depends. It depends on the type of grass and rainfall. How much rain has a big impact for me because sometimes we get a lot and sometimes we get none. For me, bermuda grass is not affected at all and tall fescue is. But, I think the tall fescue is more affected by too much water than the salt in the water. My pool overflow drain path was impacted last spring/summer and definitely has less grass. We got a lot of rain last spring. I don't recall seeing or noticing much of an impact in prior years while in drought.