Rainwater as Resource
This pattern is shaped by
Problem
In most buildings, rainwater that falls on the roof — clean, soft, and free — is treated as waste and sent to the storm drain, while the building draws treated municipal water for toilets, laundry, and irrigation.
Evidence and Discussion
A typical house in Edmonton receives roughly 100,000 liters of rain per year on its roof. Captured and stored, this is enough for toilet flushing, laundry, and all outdoor irrigation for the year. The technology is simple: gutters, a first-flush diverter, a storage tank (above or below ground), a pump, and a filter.
Therefore
collect rainwater from every roof surface and store it for non-potable use — toilet flushing, laundry, and irrigation. Size the storage to the roof area and local rainfall: roughly one liter of storage per square meter of roof per millimeter of design rainfall. Place the tank where it's accessible for maintenance. Connect it to the building's non-potable water system with appropriate backflow prevention. In cold climates, insulate or bury the tank below the frost line.