Water purification/filtering best practices

Hello,

I currently live in a town where the water isn't great and, have to find a better solution than the straight filter I have. I went through many resources and even checked Water Filtration Video to know more but,did not find anything important that would help. So I'd like to get some advice on good RO units (local roasters and cafes use RO in my area) that are designed for super-low scale home use only. The 250 liter/day units are overkill and basic filtering isn't going to cut it.

I have a GS/3, Compak K8 and use a good quality but basic filter. I generally make 3 to 5 espressos (some of which have milk) per day.

Thanks