Systems can cost from about £2500 up to £4000 plus including installation costs, depending on size of tank. Commercial systems can cost a lot more depending on size and requirement, but have a much quicker 'pay back' period.

 

The lowest costs are achieved with a new build where costs can be in the region of £1000.  Excavation works for the tank are additional requirements as is a plumbing network for the rainwater appliances and commissioning of the control appliance.  Other works such as drainage and soakaways have to be completed with or without rainwater harvesting. 

 

For a residential system the current payback period is about 15 years based on the product cost.  A commercial system payback can be as low as 3 years.  Each application is different but large roof areas enable large volumes of water to be captured.

 

 

Whole-life cost factors

In contrast to a conventional water supply and drainage system, a rainwater recycling system requires additional components, which result in higher capital costs. A whole-life-cost analysis should determine whether or not the future water cost savings can offset the higher capital costs.

Factors that influence the best-value calculations include:

• Rainfall Can you collect enough rainwater? Mean annual rainfall in England varies dramatically, with values of 500 mm in the Thames Estuary compared with 5000 mm in the Lake District. The average for England is about 900 mm. The mean annual rainfall for Scotland is nearly half as much again, at about 1500 mm.
• Pattern of water usage Domestic water usage varies greatly; daily usage of 40 litres per person is possible, although the UK average is between 100 and 160 litres a day per person. The less water households use, the more likely recycled rainwater can meet the demand.
• Building use The potential for cost-efficient recycling rainwater is excellent for commercial and institutional buildings such as schools or offices where there are large roof areas and high non-drinking water use. Furthermore, businesses may claim Enhanced Capital Allowances for rainwater harvesting systems.
• Scale of development On large projects the costs of rainwater recycling facilities can be offset against the savings from not having to construct a traditional stormwater drainage system with a treatment plant.
• Water provider The lower the cost of water and standing charges, the longer the payback period for a rainwater recycling system. Water costs are likely to increase, making rainwater recycling not only a sustainable option but a more cost-effective option.

 

Rainwater harvesting systems help to meet the Code for Sustainable Homes, BREEAM Assessments. They do so by providing up to 50% of household water requirements, increasing to around 80% in commercial/industrial/office premises which combine a large roof area with high non-potable water usage

 

 

Please feel free to get in contact with us by email or call 0845 189 9894 to discuss any of your requirements.