Galiano Island and the Southern Gulf Islands generally experience lower rainfall compared with the Lower Mainland, and Vancouver Island. Because water is often an issue on Galiano and to help preserve the water table and local aquifers, Galiano Green requires every home plan to include a rainwater harvesting system.
At a minimum, rainwater harvesting systems include a catchment system, storage tanks, pump, water treatment system and fixtures for the use of water. Depending on the design and level of water treatment and purification, harvested rainwater can be used for outdoor irrigation, domestic purposes, such as toilet flushing and laundry, and potable uses.
Some questions to ask:
How many occupants in your house?
What is the square footage of your roof collection area?
What is the square footage of your secondary collection areas?
How much water will you start with?
What size will the water tank be (in gallons)?
Will you use the communal laundry (This lowers your household water demand by 20%)
Next, you need to work out the amount of water you will need to meet the needs of your household. To help you do that, there are lots of resources on the web with more information about Rainwater Catchment Systems. Here are some we recommend:
CMHC Rainwater Catchment Guide – CMHC Rainwater Catchment Guide For Homeowners