Rain Barrel - Water Collection Calculations

The purchase of a good-size rain barrel to which a hose can be attached or a watering can filled can eliminate outdoor use of drinking/tap water. This will save you money and help reduce Greenhouse Gas (GHG) emissions.

What you pay on your monthly water bill goes towards the cost of current water and wastewater treatment and toward the ongoing creation and maintenance of treatment facilities. The water you use everyday requires large amounts of electrical energy to treat, deliver and remove wastewater/sewage from your home.

An example of the associated cost savings and GHG emission reductions by collecting rain water for irrigation is provided below. Based on a house with a 102 squared metres (1,100 squared feet) roof surface (Home Energy Chronicle SESCI) from April to October inclusive, the average rainwater collected is 35.8 cubic metres.

Greenhouse Gas Savings April to October – 7 months
35.8 cubic metres x 1.7534 kg/cubic metres (water and sewer factor) = 62.7717 kg of GHG emission reductions

Cost Savings April to October – 7 months
35.8 cubic metres of water x $3.298^* (water and sewer charges) = $118.07

^*In 2022, the water rate for residential homes (up to 60 cubic metres) = $2.0487 per cubic metre plus sewer charges of $1.2493 per cubic metre for a total of $3.298 per cubic metre.

That is, one household within the City of Edmonton, having a 102 squared metres (1,100 squared feet) roof surface, can save $118.07 on their water bill during the 7 months quoted by using rain water to water their lawn and garden. They would also reduce their share of GHG emissions by 62.7717 kg per year.