How much detergent do we need?
According to the Greater Vancouver Regional District, the people responsible for our civic water supply, Vancouver has the softest water in the country ‒ at 3.0 mg/L, we're a fraction of the 123
mg/L national average of the largest Canadian cities.
What does that mean? Well, for one, that you can cut back on your soap use. The amount of detergent you need depends up your water's softness or hardness. Simply put, soft water needs less detergent because it "works" harder.
The reason Vancouver's water is soft is that it runs quickly out of the mountains. Water in Regina, for example, spends much longer on flat land, absorbing the calcium, magnesium and other minerals that retard its reaction with soap.
Since the amount of detergent a manufacturer recommends you use is based upon moderate water hardness, says the GVRD, our soft water allows us to use little and still get the results we expect. They recommend you experiment with using just half the recommended amount.
Water hardness across Canada, from GVRD sewerage.