During a rainstorm many people wonder how much water came pouring off the roof that could have been harvested for use.

The calculation is relatively simple. All you need to know is the surface area of your house in square meters - not the roof’s surface area but the floor surface area. Generally it would be expressed in square meters.  Secondly you need a rainwater meter to tell you how much rain fell during a particular rainstorm. Generally is expressed in milliliters of rain.

All you do now is to multiply the surface area of the roof, in square meters with the amount of rain, in millimeters, and the answer you get will tell you how many litres of rainwater came running off the roof. 

During a good rainstorm of 100 millimeters a house with a surface area of 200 square meters can harvest 20 000 litres of water. That is the average monthly water consumption of a small household.

This simple calculation will inform any homeowner that rainwater harvesting presents a big opportunity to save you money and help save the environment.

There are many critical design elements  to consider if you want to design and install a system for your house. It might be worth your while getting hold of a professional supplier to assist you with the design and installation of a system.

Rainwater harvesting is not a new concept. Municipal water has been plentiful and of good quality and thus the modern generation has forgotten that many of our forefathers only had rainwater as a source of drinking water. Man now has to re-discover the process of harvesting rainwater and apply modern technology and sophistication to supplement dwindling water supplies

Once harvested the treatment of rainwater will depend on the use,  potable or non-potable. Rainwater is safe to drink  but requires proper treatment. In the last phase of treatment for potable water the correct sanitization process must be applied. This can vary from chlorination, ozonation, UV light radiation or ultra-filtration.

Generally the most cost effective systems are conceptualized in the design phase of a building. Roofing design, material selection and guttering are critical elements that need to be considered and incorporated into the design of the structure. Thus when planning on building or renovating – rainwater harvesting should be incorporated into the design.

Existing buildings and structures can easily be converted to harvest rainwater effectively.

Rainwater harvesting and water conservation should be on the agenda of every company or homeowner. It is a cost effective investment that can make a significant financial reduction to your monthly utility bill.