Addicted to water

My niece has a water issue. She is starting to drink too much water. She is 7 years old. She drinks 6-7 Dasani water bottles a day. Each water bottle is 16.9 fluid oz. I understand it's hot outside, but I'm afraid she'll drink more than her body can take and end up drowning herself. So daily, she intakes about 101.4 to 118.3 Ounces of Water. Is this amount okay or is she intaking too much? She uses the bathroom to pee about 3-4 times a day. I don't know if that was relevant or not.