Savings from a rainy day
February 1st 2005

The sustainable use of water is becoming a critical issue for industry and commerce in the UK. Increasing pressures on water resources has led to rising costs, and companies are now looking for new ways to save money. The installation of rainwater harvesting systems (RHS’s) into industrial and commercial sites can offer significant benefits and have been included on The Water Technology List

The Water Technology List (WTL), developed and managed by Defra and the Inland Revenue, in partnership with Envirowise, offers an incentive for industry to invest in technologies which use water sustainably,making for a win-win situation both environmentally and economically.

The WTL encourages a more sustainable use of water, but investing in any eligible equipment also offers a tax incentive to all businesses that pay corporation and income tax in the UK.

Modelled on the Government’s Enhanced Capital Allowance (ECA) scheme for approved energy saving products, the WTL allows businesses to write off 100% of investments in qualifying sustainable technologies and products against tax in the year of investment. For example, if a company paying 30% corporation tax buys eligible equipment worth £1000, then their tax relief will be worth £300 in the first year.

Water is our most precious natural resource and something that most of us take for granted.We are now increasingly becoming aware of the importance of water to our survival and its limited supply.

Rainwater Harvesting helps address the limited supply, as it is the collection of water that would otherwise go to the drainage system, into the ground or lost to the atmosphere through evaporation.

The harvesting of rainwater simply involves the collection of water from surfaces on which rain falls, and subsequently storing this water for later use.Normally water is collected from the roofs of buildings and hard standings, such as driveways. Water can also be collected in dams from rain falling on the ground and producing runoff, and other large surfaces such as roofs of car parks are also ideal for rainwater harvesting and can provide a significant volume of water from a medium sized area.

RHS’s can be installed in both new and existing buildings, and the resulting water used for many purposes depending on the level of treatment within the process.

RHS’s are a proven technology, and issues such as contaminants like oil can be overcome by removing prior to filtration. The rainwater collected from roof or car park surfaces is directed via the drainage system to a filtration unit that removes organic matter such as leaves and oil etc. Filtration units form the first stage of the RHS. The filtration units are designed specifically for RHS’s and are available and sized according to the surface size of the collection area.

Water produced from this first stage can be used in any application where health and safety is not a key issue. An example of this would be in commercial establishments, for toilet flushing and irrigation or in industrial processes for cooling and cleaning activities, such as floor washing or vehicle washing.

Subsequent levels of treatment required within the system will depend on the quality of the water demanded for a specific process or duty, and the quality of the incoming water. RHS’s have the technology to address all of these requirements.

Generally a typical system consists of the following; rainwater collection; rainwater filtration equipment; pumps for the transfer of water; water storage tank(s); monitoring and control unit(s) including mains water back-up; and further water treatment equipment (if present.) Industry and commerce account for a significant proportion of all water consumption, and most sectors use large volumes for process purposes. Although some industries abstract water from rivers and boreholes,much of the water used is taken directly from the public supplies, and has therefore been treated to potable quality standards.

Although RHS’s do not inherently save water, they can offer an alternative source to mains water and the economic benefits can be significant, but will vary depending on volume of water consumed, the water supply company, and the time of year. According to figures for the UK the average cost of water supply and sewerage services (per m3) has more than doubled over the last 15 years and prices are set to rise further over the next few years.

It is understood that around 450 units per year are being installed across the UK, compared with other parts of Europe where the installation rate is much higher. This is due partially to economic factors.

The availability of ECAs via the Water Technology List, will provide a wider incentive for the use of rainwater harvesting equipment both in industry and commerce. Of the 450 units being installed per year, around half are thought to be commercial systems which vary widely in price, with an average cost of between £3500 - £10 000.

To find out more about registering or purchasing products on the WTL, visit www.ecawater.

gov.uk or call 0800 585794.

Currently, the categories of the qualifying technologies include:

• Flow Controllers • Meters and Monitoring Equipment • Leakage Detection Equipment • Efficient Toilets • Efficient Taps • Rainwater Harvesting Equipment

Case study on use of a Rainwater Harvesting System: Gusto’s Venue, a nightclub in Newark, has installed a rainwater harvesting system.The system takes water from the roofs, filters it and then stores it underground under the dance floor.The overflow goes to local drains.This water is then used for toilet and urinal flushing.

The system delivers the following benefits:

• The club saves on mains water charges by approximately £600 per year.

• The system has the environmental benefit of reducing the storm water run off from the building.

“The benefits of using a rainwater harvesting system have been both financial and environmental – Gusto's Venue is able to save itself money by using this technology whilst also reducing its impact on the environment.”– Jeremy Heppell, financial director.

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