Why does the water or soda at some restaurants taste like plant or grass?

It's kind of weird actually. We eat out quite a bit and have noticed that the water and sodas at restaurants in certain areas have a planty or grassy taste to it. Sometimes it's so bad that we can't drink it. What causes this?Why does the water or soda at some restaurants taste like plant or grass?
most likely the fungi/algae which are chlorophyll rich,,, I know with beers certain places in town always have untasty funk on tap,, so I always avoid those places. Some have old systems that have piping that cant be cleaned properly, or they just have really slow business or they simply just too lazy tooo ever clean something right, including your glass %26amp; fork, yech!!
They need to clean the dispensers, there growing bacteria and algae, hence the taste.Why does the water or soda at some restaurants taste like plant or grass?
Vegan restaurant?
second that.also flourine, chlorine bleach cleaner ,and powdered chemical sanitizer