Peeling back the Pavement - POLIS Water Sustainability Project

Blueprint principle 2: let rain do the work
implement widespread rainwater harvesting
First Step
Promote Non-Potable Water for All Irrigation
Ensure all institutions, city parks, boulevards, recreation areas, swimming
pools, and golf courses are using rainwater for irrigation and
other non-potable uses, especially outdoor uses.
Overcome Code Restrictions
Building and plumbing codes must be amended to allow for the
widespread use of rainwater for indoor non-potable uses. Overcoming
barriers and promoting this “off the grid” water supply requires all
levels of government to take an active role. National, provincial,
and territorial building and plumbing codes should be updated to
differentiate between greywater, non-potable water, and rainwater.
Building codes should explicitly permit and mandate the use of
rainwater harvesting and greywater systems in homes and commercial
buildings for irrigation, clothes washing, toilet flushing, and in heating
and cooling units.
National, provincial, and territorial codes must explicitly expand
permitted end uses. Until recently, it was difficult to get approval to use
non-potable water supplies in dwellings in Canada. However, both the
National Building Code (NBC) and the National Plumbing Code (NPC)
now permit the use of non-potable water for some uses, such as toilet
flushing. In its proposed revisions of provincial building and plumbing
codes, Ontario has gone a step further by allowing clothes washers to
be connected to rainwater supplies.
next Steps
Develop Provincial/Territorial Guidelines and Policy Support
Mitigate concerns about liability for innovative communities by
developing mechanisms for flexibility or standardized technical
requirements related to green infrastructure and rainwater harvesting;
best management practices regarding end uses, treatment, and
maintenance; and general guidance on how to implement rainwater
harvesting on a widespread scale.
Develop Local Government Support and Guidelines
Adapt provincial and territorial guidelines (or technical requirements)
to local circumstances. Ensure that guidelines are adaptable and able
to change as best practices evolve. Incorporate the guidelines into
community and regional planning documents.
Mandate Dual Plumbing for All New Developments
Look to the future and ensure all new developments contain purple
pipes, regardless of whether they are immediately connected to a
non-potable water source.
Overcome Cost Barriers
Introduce incentives for property owners to implement rainwater
harvesting such as rebate programs (including installations) and full
cost conservation-based pricing of municipal water supply. To realize
economies of scale, start with large properties such as institutions and
industry. 41