(80100) Joensuu - 2 Voimatie

There's a tap with drinking water available in the marked corner. You need to get the key to turn on the tap, which you get from the Prisma info point (just enter the building through the next door and go to the right, you'll see it there). I just had to say that I wanted to fill up some water and got the key for free. Water tastes good :) Also, there are a few toilets right by the entry, inside the building.