Hibiny.com reports that Kandalaksha and area water is safe before it enters the distribution system, and if I correctly understood the story, it remains borderline acceptable when delivered to households through dirty rotten pipes.
Still, the official advice is to boil water before drinking it.
My own nose tends to be skeptical about this advice, and I recommend you get your water from one of several springs around the city.
We use two: in the city park
and on the Kandalaksha to Umba road, ~5km from Kandalaksha, on the left side.
Or buy bottled stuff.