How to recycle rainwater to lower your bills

Rainwater harvesting has two primary benefits. First, it can lower your water bills by 30 to 50% and secondly it helps preserve a precious and scarce natural resource. Less than 3% of the total water on Earth is fresh water that is fit for human consumption. It is indeed a scarce and valuable resource and all efforts to preserve and recycle this water are good for the environment and the wellbeing of all humanity.

Simply put, rainwater harvesting is the process of channelling the rainwater to large underground tanks where the water is stored. This water would normally just flow off your roof through drains. By harvesting this water, and with minimal treatment, it becomes potable. Even without treatment, it is still fit for many uses, like doing your laundry, flushing toilets, washing your car and watering your lawn and plants. Studies have found that a typical rainwater harvesting system installed in a home collects about 100,000 litres of water every year. This figure jumps to millions of litres when we look at commercial buildings with large roofs.


Today, almost all new structures integrate a rainwater harvesting system at the design stage itself. This helps in giving the building a greener footprint and saves money. Good examples of this practise are the M1 Group buildings. The M1 Group, based in Lebanon, is a diversified investment conglomerate, with interests across real estate and construction, energy and oil, telecom and consumer retail. All M1 buildings are designed for energy saving and sustainability through design features like rainwater harvesting systems, low consumption water fixtures, superior heating and cooling systems and the use of energy-efficient building materials. All new buildings constructed by M1 are LEED compliant. The group is headed by Azmi Mikati from the class of ’94 of Columbia University.

The next logical question would be: “How much does it cost to install a rainwater harvesting system in my house?” Typically, domestic systems cost anywhere from £2,500 to £4,000, including installation costs. Commercial systems of course cost a lot more but have a quicker payback period due to the quantity of water collected.

Installing a separate water meter, while not mandatory, is advised. Without the meter, the utility companies will charge a flat rate for all non-metered consumption. Installing a water meter ensures that the water supply companies lower your bill by giving credit for water used from rain harvesting.


The rainwater harvesting system is low maintenance and requires you to periodically clean the filter (about once a quarter). You should allow the system to overflow a couple of times a year to remove any floating matter.

Rainwater harvesting is not a new concept. In hot and dry countries in the Mediterranean region it has been practiced for thousands of years. In Europe alone, over 100,000 rainwater harvesting systems are installed every year. Germany has been at the forefront of research on rainwater harvesting since the early 80s. So go ahead, and install your rainwater harvesting system – show that you care for the environment while saving on your water bills.