Grey water recycling & Rainwater harvesting

Why is it important?

Grey water recycling within homes is the process of taking used water from showers, baths and wash hand basins, filtering it and storing the filtered water for re-use.

How is it installed?

There are many different systems for grey water recycling varying - from ones that are located underground like rainwater harvesting and collect water from the whole house - to ones that can be located in a single bathroom and collect water from just that bathroom to feed the toilet.

Where possible, install a gravity system which requires a header tank to be installed in the loft area which feeds from both the harvested water and the mains supply - the mains supply will only be used in the event of the rainwater running out. The advantage of this system is that it still works if there is a power cut or pump failure.

If it is not possible to install a gravity system, such as in a property with a habitable roof, then a direct system should be installed. This system requires a mains supply feed back to the harvesting tank that is controlled by a solenoid valve in order to keep the system running when there is no rainwater left in the tank.

Hints & Tips

  • The systems are easy to install and are often maintenance free

  • Rainwater Harvesting has an underground storage tank that should be installed on a concrete plinth and then encased in concrete to ensure the water table doesn't lift the tank out of the ground when there is no water inside.

  • Ensure the pipework from the rainwater harvesting tank to the inside of the house is installed with black and green striped pipework, so it is not mistaken for a blue mains water pipe.

  • The inclusion of rainwater harvesting can aid planning applications as local authorities increasingly expect applications to demonstrate Sustainable Drainage.