Maintenance Requirements of a Rainwater Harvesting System
Many larger commercial properties constructed in the past 25 years in the UK will have a rainwater harvesting system installed. The rainwater harvesting system will capture rainfall from the facility’s roof area and recycle the rainwater to provide a non-potable water supply to the building and typically has a lifespan of 20 years provided the system has been maintained effectively. Rainwater harvesting systems are mostly used to provide a water supply to toilets within a building, although systems can often be connected to external bib taps and other appliances. Rainwater harvesting systems should be included within any planned preventative maintenance schedule for a building to ensure a constant supply of water to points of use.
Locating the rainwater harvesting system
For facility managers who may be unsure if they have a rainwater harvesting system or where the system is located, there are several ways to identify whether a system is present in the building.
- Checking for a main storage tank – all rainwater harvesting systems will have a main storage tank located above or below ground. The main storage will house a pre-tank mesh filter which will be visible from a manhole entry point.
- Checking for mechanical and electrical equipment – Rainwater harvesting systems will have an electrical control panel located within an internal plant room. These will usually be located on a wall with a water meter located close by.
- Identification tape on the pipework – pipework associated with rainwater harvesting will be labelled with black and green identification tape in accordance with WRAS (water regulations approval scheme) regulations. The tape will also show the text ‘reclaimed water supply’ or ‘harvested water’.
Once the rainwater harvesting system has been located within the building, give our maintenance team a call and we will be on hand to assist.
Once a rainwater harvesting system has been identified within a building, the system will require an initial survey followed by regular maintenance, including;
System Servicing - Rainwater harvesting systems will require a service every six months by a specialist engineer. Stormsaver offers bi-annual maintenance agreements where our engineer will electrically test the control panel to ensure safe operation, remove excess debris from the pre-tank mesh filter, clean any filters and water meters, and complete a visual inspection of the water quality within the main storage tank. Learn more here.
Tank Cleaning – The main storage tank and header tank of a rainwater harvesting system require a full tank clean every 2 years. The frequency may increase in areas of intense bird activity or where systems are located near forested areas or by the coast. The tank cleaning process will involve our operatives physically entering the tank to clean it with a sodium hypochlorite cleaning solution. Tank cleaning ensures high water quality levels and protects the pumps from a build-up of excess sediment on the base of the tank. Learn more here.
Legionella Testing – Regular legionella testing of the system should be completed as part of a wider water hygiene risk assessment within a building. Stormsaver can provide rapid legionella testing during our six-monthly service visits. Just like any water storage system, tanks located in areas of higher temperatures are more prone to the development of legionella. Learn more here.
Other Maintenance Considerations
Confined Space Classification – Some rainwater harvesting systems have pipework located in the main storage tank which is classified as ‘confined space’ by the Health and Safety Executive; therefore, two qualified engineers are required to safely service the system increasing the cost of maintenance. Any pipework that is located 300mm below ground level requires two engineers. Stormsaver offers pipework upgrades to bring all associated pipework up to a sufficient depth meaning the cost of future service visits can be significantly reduced and improve safety for engineering staff.
Roof and Gutter Cleaning – Rainwater harvesting systems offer the best quality of water when the roof space where rainfall is collected is clean and free of debris. Where low levels of water quality are experienced, a roof clean of the collecting area should be considered.