(1)
Non- potable rainwater harvesting systems and their connections shall be designed, fabricated and installed in accordance with this Subsection and good engineering practice. (See Note A-7.7.2.4.(1))
(2)
Non- potable rainwater harvesting systems shall not collect water discharged from an evaporative heat rejection system.
(3)
Non- potable rainwater harvesting systems shall be provided with a means to treat the harvested rainwater in such a manner that the quality of the delivered non- potable water conforms to appropriate provincial or territorial requirements or, in the absence of such requirements, the systems shall conform to Sentence (4). (See Note A-7.7.2.4.(3) and (4))
(4)
Except as provided in Sentence (3), non- potable rainwater harvesting systems shall be provided with
(a)
a water treatment system consisting of
(i)
a debris screen with a mesh size of not more than 6 mm ahead of the storage tank inlet,
(ii)
a first-flush diversion system with a capacity of not less than 0.3 L/m
(iii)
a calming inlet or settling chamber ahead of the storage tank inlet,
(iv)
a device to prevent the entrainment of sediment into the pump, and
(v)
where the harvested rainwater is used for an indoor application, a filter with a mesh size of not more than 50 μm ahead of the storage tank inlet, or
(b)
a means to treat the harvested rainwater in such a manner that the delivered non- potable water contains not more than the maximum acceptable levels of contaminants stated in CSA B805 / ICC 805, “Rainwater harvesting systems.” (See Note A-7.7.2.2.(1) and 7.7.2.4.(3) and (4))
(5)
Where the static pressure at any fixture in a non- potable rainwater harvesting system may exceed 550 kPa, a pressure-reducing valve shall be installed to limit the maximum static pressure at the fixture to 550 kPa.
(6)
Storage tanks in non- potable rainwater harvesting systems shall be designed and installed in accordance with
(a)
CAN/CSA-B126.0, “General requirements and methods of testing for water cisterns,” and
(b)
CAN/CSA-B126.1, “Installation of water cisterns.”
(7)
Storage tanks in non- potable rainwater harvesting systems shall be equipped with an overflow that directs excess rainwater to
(a)
a public storm sewer,
(b)
a public combined sewer,
(c)
a storm water management system, or
(d)
a designated storm water disposal location.
(8)
Where the storage tank outlet is located below the level of the adjoining street, the storage tank overflow required by Sentence (7) shall
(a)
with an indirect connection that is not located within the building, or
(b)
be equipped with a backwater valve.
(9)
Make-up water connections to non- potable rainwater harvesting systems shall
(a)
be equipped with a reduced pressure principle backflow preventer, or
(b)
have an air gap.
(10)
Where a fixture combines water from a non- potable rainwater harvesting system and potable water at the fixture supply fitting, the potable water system shall be protected by a backflow preventer as described in Sentence 7.6.2.1.(3).