Rainwater Harvesting 101

how can you reuse rainwater?

rainwater harvesting household uses

Rainwater harvesting is a smart and effective way to conserve water. It is also an environmentally friendly choice that can help reduce your water bills.

Rainwater design can be used for a variety of purposes such as watering plants, washing your car, or flushing your toilet.

By capturing and storing rainwater, you can reduce your reliance on municipal water sources and contribute to a more sustainable future. 

Give rainwater design a try and see how it can benefit you and the environment.

Frequently asked questions

Rainwater is fresh precipitation straight from the sky that hasn’t touched the ground.

Water demand includes all indoor and outdoor uses. To calculate your water storage requirement, you have to understand your monthly indoor and outdoor water demands. 

You can collect rainwater for domestic uses, agricultural or commercial uses.

The most common uses of rainwater include non-potable uses such as toilet flushing, gardening, and car washing or potable uses such as drinking and cooking, dishwashing, and showering.

Let us help you determine how big your storage tank should meet all your water demand needs.

Let us start with sizing of your water storage tank but first we have to ask you a couple questions about your water situations. 

Let us help you to determine the size of your water storage tank to ensure that you will

  • Have enough water for the entire year
  • Not run out of water in the middle of the summer
  • Avoid subsidizing your water with untested water from outside sources, and
  • Minimize the excessive overflow from the cistern in the winter months.

The total amount of water you can collect from your roof via rainwater harvesting depends on:

  • The area of your roof (the area measured as the horizontal projection of the roof).
  • The efficiency of your rainwater harvesting system, including the system losses due to evaporation, type of roofing material, and any losses or leaks in the water conveyance system.

How to calculate your harvest potential?

Average Rainfall x Efficiency x Roof Area

It is helpful to understand the differences between metric and imperial measurement systems used in North America. Check the conversion system.

For example:

  • 1″ of rain on 1 square foot of roof area produces 0.52 Imperial gallons of water
  • 1 mm of rain on 1 square meter of roof area produces 1 Litre of water

The roof area is measured by the horizontal footprint of the top, not its surface area. 

Length x Width of each segment of the roof Area 

The catchment area should be of a material suitable to allow for the end-use of the collected rainwater 

Pre-storage filtration prevents coarse material from entering the system and removes suspended
contaminants (i.e., gutter screening, debris filters).

Storage tanks and conveyance systems have to comply with standards for their construction materials
and potable water.

No, all plumbing connections inside a building require a certified plumber

water storage tank with a boy
Let’s begin by calculating the necessary water storage capacity based on your water usage,  rain patterns in your area and the size of your roof catchment.