In built-up areas the water is safe to drink , however, some areas it is not safe to drink the tap water at all! So we rather recommend that you drink bottled water at all times to prevent any illness. Do not use the tap water to rinse your mouth when brushing your teeth!  Every lodges/camps provides  bottle water in the rooms. Ice is generally fine to consume, but sometimes it is better to be cautious. We advise you to rather drink bottled water at all times in Tanzania!