It may be hard to believe, but the calendar tells us spring has arrived! Soon many Calgarians will be outside planting, turning compost piles and capturing rainwater as they tend to their lawns and gardens.
Using rainwater that runs off your roof can be an efficient way to conserve water and give the grass a drink during the heat of summer but there a few things that need to be considered when using run-off.
Asphalt shingles generally do not contain heavy metals or toxic chemicals and are considered safe in groundwater. HOWEVER, roofs are exposed at all times to environmental contaminants: bird and rodent droppings, wind-blown debris including plant, algae & insect particles and more. This exposure has the potential to make run-off harmful to people, pets and ingestible plants.
do NOT use run-off for human or pet use such as drinking, cooking or washing - any cistern system intended for human use would need to have comprehensive filtering and testing procedures in place
do NOT apply run-off directly to fruits, herbs or vegetable plants - you can use the water instead to soak the surrounding areas around the garden patch so that surrounding dry soil doesn’t leach moisture from the garden soil
It’s okay to:
use run-off to water the lawn and ornamental trees & shrubs that do not bear fruit or vegetables