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This article is about outdoor, residential systems. For larger, multi-residential or commercial integrated systems, see [[Rainwater harvesting]]   

This article is about outdoor, residential systems. For larger, multi-residential or commercial integrated systems, see [[Rainwater harvesting]]   

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==Overview==

==Overview==

Rain barrels are an above ground form of rainwater harvesting, typically used in residential settings. The precipitation flows from the roof, to the guttering and down the downspout before being diverted to the rain barrel for storage.

Rain barrels are an above ground form of rainwater harvesting, typically used in residential settings. The precipitation flows from the roof, to the guttering and down the downspout before being diverted to the rain barrel for storage.

[[File:Leaf_Screens.jpg|thumb|Leaf screens can be included along the eaves-troughs (above) or integrated with the downspout (below)]]

[[File:Leaf_Screens.jpg|thumb|Leaf screens can be included along the eaves-troughs (above) or integrated with the downspout (below)]]

[[File:RainBarrel.jpg|thumb|The screen on this rain barrel prevents mosquitoes from entering and screens leaves from the water.]]  

[[File:RainBarrel.jpg|thumb|The screen on this rain barrel prevents mosquitoes from entering and screens leaves from the water.]]  

<h3>Watershed scale</h3>

===Watershed scale===

Traditional rain barrels require a high degree of owner compliance to perform as a reliable stormwater management control strategy at watershed scale. To overcome this limitation, electronically monitored and controlled rain barrels are  a new adaptation on the market in Ontario[https://www.raingrid.com/]. This system forecasts rain and automatically discharges the contents of the rain barrel to a designated infiltration area of the property in advance of the storm.   

Traditional rain barrels require a high degree of owner compliance to perform as a reliable stormwater management control strategy at watershed scale. To overcome this limitation, electronically monitored and controlled rain barrels are  a new adaptation on the market in Ontario[https://www.raingrid.com/]. This system forecasts rain and automatically discharges the contents of the rain barrel to a designated infiltration area of the property in advance of the storm.   

<h3>Site Scale</h3>

===Site Scale===

Place in the Treatment Train

Place in the Treatment Train

In most cases the catchment area will be the roof of the building and the rain barrel will be the first interception of water from the downspout. Planning questions:

In most cases the catchment area will be the roof of the building and the rain barrel will be the first interception of water from the downspout. Planning questions:

*Do the downspouts require reconfiguration?  

*Do the downspouts require reconfiguration?  

It is recommended that an overflow strategy be part of designing a rain barrel system. Excess water should be directed away from the property foundations. Suitable discharge points for overflow include: a [[Rain Gardens|rain garden]], a [[Infiltration Trenches|french drain]], or the base of a [[Trees|tree]].

It is recommended that an overflow strategy be part of designing a rain barrel system. Excess water should be directed away from the property foundations. Suitable discharge points for overflow include: a [[Rain Gardens|rain garden]], a [[Infiltration Trenches|french drain]], or the base of a [[Trees|tree]].

<h4>Cistern</h4>

==Cistern===

Expansion caused by freezing water will damage the barrel. The easiest way to prevent this damage is to  drain and disconnect the system in advance of [[Winter#Freezing and Expansion|freezing temperatures]][http://climate.weather.gc.ca/climate_normals/].

Expansion caused by freezing water will damage the barrel. The easiest way to prevent this damage is to  drain and disconnect the system in advance of [[Winter#Freezing and Expansion|freezing temperatures]][http://climate.weather.gc.ca/climate_normals/].

==Design==

==Design==

<h3>Filter</h3>

===Filter===

The water in the barrel will remain fresher for use if leaf litter and other debris excluded. Screens can be installed on the eavestroughs, in the downspout, or at the top of the cistern. These types of screens  are not designed to capture small particles and chemical pollutants. However, this fine material is usually first to wash off surfaces at the start of the storm. A <em> first flush diverter </em> is a simple, automated, mechanical device which prevents this first 'dirtier' part of the stormwater from being stored. Screens, filters and diverters should be in easily accessible locations, so that they can be inspected and cleared of debris periodically.   

The water in the barrel will remain fresher for use if leaf litter and other debris excluded. Screens can be installed on the eavestroughs, in the downspout, or at the top of the cistern. These types of screens  are not designed to capture small particles and chemical pollutants. However, this fine material is usually first to wash off surfaces at the start of the storm. A ''first flush diverter'' is a simple, automated, mechanical device which prevents this first 'dirtier' part of the stormwater from being stored. Screens, filters and diverters should be in easily accessible locations, so that they can be inspected and cleared of debris periodically.   

<h3>Sizing Barrels</h3>

===Sizing Barrels===

Roof catchment area can be estimated using one of many online digital maps. e.g. Distance can be measured on Google maps by right clicking on the desired start point. <br>

Roof catchment area can be estimated using one of many online digital maps. e.g. Distance can be measured on Google maps by right clicking on the desired start point. <br>

1 mm of rain landing on 1 m² of roof top  produces 1 litre of water to store. <br> So a 5 mm storm on a 75 m² roof would require 375 L of storage volume. <br>

1 mm of rain landing on 1 m² of roof top  produces 1 litre of water to store. <br> So a 5 mm storm on a 75 m² roof would require 375 L of storage volume. <br>

Many people choose to reuse or recycle a container as a rain barrel or cistern. Re-purposed containers should be screened to prevent [[Wildlife#Mosquitoes|mosquitoes]] from breeding, and should be opaque to prevent algae from growing.  

Many people choose to reuse or recycle a container as a rain barrel or cistern. Re-purposed containers should be screened to prevent [[Wildlife#Mosquitoes|mosquitoes]] from breeding, and should be opaque to prevent algae from growing.  

===Performance===

===Performance===

<h3>Water Quantity</h3>

===Water Quantity===

The use of rain barrels (190L) across a watershed of 100 residential units has been modelled for a number of U.S. cities[http://onlinelibrary.wiley.com/doi/10.1111/jawr.12038/abstract]. In Philadelphia and Milwaukee (reflecting the most similar climates to Southern Ontario) the use of rain barrels for irrigation only, provided an annual stormwater reduction of less than 2%.  

The use of rain barrels (190L) across a watershed of 100 residential units has been modelled for a number of U.S. cities[http://onlinelibrary.wiley.com/doi/10.1111/jawr.12038/abstract]. In Philadelphia and Milwaukee (reflecting the most similar climates to Southern Ontario) the use of rain barrels for irrigation only, provided an annual stormwater reduction of less than 2%.  

<h3>Water Quality</h3>

===Water Quality===

The [https://www.ontario.ca/laws/regulation/120332 Ontario building code (OBC)] requires only that water collected from rooftops be "free of solids" for irrigation use in an external system such as a rain barrel.

The [https://www.ontario.ca/laws/regulation/120332 Ontario building code (OBC)] requires only that water collected from rooftops be "free of solids" for irrigation use in an external system such as a rain barrel.

There is a draft of [https://www.iccsafe.org/wp-content/uploads/110116-Draft-CSA_ICC-B805-Rainwater-Harvesting.pdf CSA B805 draft] currently under review. The scope of the document includes single family dwellings. But the guide is still under review and may not account for rain barrel systems when officially published.  

There is a draft of [https://www.iccsafe.org/wp-content/uploads/110116-Draft-CSA_ICC-B805-Rainwater-Harvesting.pdf CSA B805 draft] currently under review. The scope of the document includes single family dwellings. But the guide is still under review and may not account for rain barrel systems when officially published.  

Outdoor barrels for the residential market can cost up to $300, these have larger capacity and smart sensors.  

Outdoor barrels for the residential market can cost up to $300, these have larger capacity and smart sensors.  

==Incentives and Credits==

==Incentives and Credits==

<h3>Ontario</h3>

===Ontario===

*[http://www.peelregion.ca/watersmartpeel/residents/rainbarrels.htm Region of Peel]

*[http://www.peelregion.ca/watersmartpeel/residents/rainbarrels.htm Region of Peel]

*[http://www.halton.ca/cms/One.aspx?portalId=8310&pageId=11372 Halton Region]  

*[http://www.halton.ca/cms/One.aspx?portalId=8310&pageId=11372 Halton Region]  

*[[Rainwater harvesting]]

*[[Rainwater harvesting]]

==External Links==

==External Links==

<h3>Proprietary Systems</h3>

===Proprietary Systems===

{{:Disclaimer}}

{{:Disclaimer}}

*[https://harvestingrainwater.ca/store/ CleanFlo]

*[https://harvestingrainwater.ca/store/ CleanFlo]

*[https://www.raingrid.com/ RainGrid]

*[https://www.raingrid.com/ RainGrid]

*[http://www.rainxchange.com\ RainXchange]

*[http://www.rainxchange.com\ RainXchange]