Changes

[[File:STEP Minto Cistern P1 - Copy.jpg|thumb|Rainwater harvesting is commonly employed on zero-lot-line projects like downtown condos. This cast in place concrete vault in one corner of the parking level is a typical design.]]

[[File:STEP Minto Cistern P1 - Copy.jpg|thumb|Rainwater harvesting is commonly employed on zero-lot-line projects like downtown condos. This cast in place concrete vault in one corner of the parking level is a typical design.]]

This article is about large, integrated rainwater harvesting systems. For smaller, seasonal, outdoor, residential systems, see [[Rain barrels]]   

This article is about large, building-integrated rainwater harvesting systems. For smaller, seasonal, outdoor systems, see [[Rain barrels]]   

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==Overview==

==Overview==

The origin of the harvested water affects the permissible end uses. Some of the most common uses include irrigation and flushing or toilets and urinals. As mixed source water can only be applied to the more limited end uses, selecting the catchments for a RWH system requires careful consideration.

The origin of the harvested water affects the permissible end uses. Some of the most common uses include irrigation and flushing or toilets and urinals. As mixed source water can only be applied to the more limited end uses, selecting the catchments for a RWH system requires careful consideration.

*The [https://www.ontario.ca/laws/regulation/120332 Ontario Building Code (OBC)] regulates the use of harvested rainwater as one of many non-potable water sources. <em>"Rainwater means storm sewage runoff that is collected from a roof or the ground, but not from accessible patios and driveways."</em>

*The [https://www.ontario.ca/laws/regulation/120332 Ontario Building Code (OBC)] regulates the use of harvested rainwater as one of many non-potable water sources. <em>"Rainwater means storm sewage runoff that is collected from a roof or the ground, but not from accessible patios and driveways."</em>

*The [https://www.iccsafe.org/wp-content/uploads/110116-Draft-CSA_ICC-B805-Rainwater-Harvesting.pdf CSA  standard] separates <em>"roof runoff"</em> from all other sources, including landscaped areas and green roofs. Collectively the green roof/landscaped and paved areas result in <em>"stormwater runoff."</em>   

*The [https://store.csagroup.org/?cclcl=en_US| CSA standard B805-18/ICC805-2018] separates <em>"roof runoff"</em> from all other sources, including landscaped areas and green roofs. Collectively green roofs, landscaped and paved areas result in <em>"stormwater runoff."</em>   

The current disparity between these two definitions affects all vegetated landscapes including green roofs. Confusion over terminology and regulation has been identified as a significant barrier to implementation of RWH since 2010[http://www.ryerson.ca/content/dam/water/education%20and%20outreach/GreenInfraTO/Identifying%20Barriers%20to%20Widespread%20Implementation%20of%20Rainwater%20Harvesting%20for%20Urban%20Household%20Use%20in%20Ontario.pdf].

The current disparity between these two definitions affects all vegetated landscapes including green roofs. Confusion over terminology and regulation has been identified as a significant barrier to implementation of RWH since 2010[http://www.ryerson.ca/content/dam/water/education%20and%20outreach/GreenInfraTO/Identifying%20Barriers%20to%20Widespread%20Implementation%20of%20Rainwater%20Harvesting%20for%20Urban%20Household%20Use%20in%20Ontario.pdf].

===Cistern and Pipework===

===Cistern and Pipework===

Cisterns must be installed in locations where native soils or the building structure can support the load associated with the volume of stored water. <br>

Cisterns must be installed in locations where native soils or the building structure can support the load associated with the volume of stored water. <br>

==Design==

==Design==

[[File:RAINWATER HARVESTING TANK 550x550.jpg|thumb|Large cistern being installed underground]]

[[File:RAINWATER HARVESTING TANK 550x550.jpg|thumb|Large cistern being installed underground]]

[[File:RWH.gif|border|300 px|Conceptual diagram of an underground cistern being used for irrigation]]

[[File:RWH.gif|thumb|Conceptual '''gif''' of an underground cistern being used for irrigation]]

[[Rainwater Harvesting: Sizing and Modelling]]

[[Rainwater Harvesting: Sizing and Modelling]]

===Catchments===

===Catchments===