The 2006 Ontario Building Code now permits using storm sewage or greywater to flush toilets, urinals and for priming traps.

A permit is required prior to installing either system.

Storm sewage is water that has been discharged from a surface as a result of rainfall, snow melt or snowfall and collected for use.

Greywater is sanitary sewage from sinks or bathtubs.

Both storm sewage and greywater are considered non-potable sources of water so it is important to note that these systems must be clearly and permanently marked and cannot be interconnected with a potable water system.