How much water does the average Montrealer use every day in their home? Enough to fill two bathtubs. That’s 225 L of clean water. The province-wide average is even bigger, at 400 L per person every day, according to McGill University. How much fresh water do private industries use per year? About 10 times household use, Statistics Canada notes. Most of our household water use comes from addressing basic physical needs. 65 per cent comes from toilet flushing and bathing. The rest is accounted for in our drinking, preparing meals, and cleaning (including laundry).