Rainwater harvesting can be applied to most buildings, regardless of size and purpose. However, due to certain practical issues, it is a technology that is generally best suited to new-build properties, as the system can be easily designed in at the start of the project. Having said that, it is some times desirable or necessary to incorporate it into an existing building. Retro-fit rainwater harvesting systems are not generally readily available as most suppliers only target the new-build market. In response, we aim to provide advice and assistance for those who wish to collect water from their existing property.
There are certain potential problems with any existing property from the point of view of collecting rainwater, so careful consideration is advised:
- it is conventional to install an underground storage tank. To retro fit, this could be very disruptive and expensive on an existing site and may even entail re-routing of some services.
- it will probably also necessitate re-laying some of the stormwater drainage. Fitting a tank and filter unit into an existing drainage scheme will involve changing the levels of some of the pipework.
- the drainage system supplying a rainwater harvesting scheme should only carry water from roof surfaces. If the existing drainage also takes water from trafficked areas, or worse still, from ‘grey’ water sources such as baths, basins etc. (not uncommon, particularly on older properties), then the drainage will require alterations.
- some changes to the rainwater downpipes and / or the internal plumbing will be required.