It’s raining; it’s pouring, and yet the old man appears to be snoring

Could rainwater reuse technology help the UK tackle water storage and drought?

STREAM Research Engineer and Researcher for Centre for Water Systems, Sustainable Water Management, Peter Melville-Shreeve takes a look at the technology which is waiting in the wings to help us address problems of drought.

When will the Old Men in central government provide support for rainwater reuse technologies in the UK? Do we need for the taps to run dry, or our cities to flood even more frequently? The technology is waiting in the wings and yet, despite terrible drought conditions in 2012, followed immediately by record flooding, nothing has been done. The latest market data from 2009 shows that a measly 5,000 rainwater harvesting (RWH) systems are installed each year.

A dried up riverbed.

A dried up riverbed.

The RWH technology captures water from roofs and allows it to be reused instead of precious drinking water for uses such as WC’s and garden irrigation. It reduces the impacts of floods and droughts and yet the policymakers continue to ignore its potential. If we take the 2012 Drought as an example, the government had serious concerns that there might not be enough water to supply the Olympics!

Harvesting rain can reduce flooding and drought.

Harvesting rain can reduce flooding and drought. Image by Peter Melville-Shreeve

“A Western European country”, I hear you mutter, “where it rains 24/7, running out of water. Surely not?” Well no… not quite… not yet. So let’s introduce climate change to the equation. A mythical beast that will change our rainfall in ways which only supercomputers can comprehend. We need to act now to build resilience into our water infrastructure. RWH is the ideal tool to provide additional capacity within our water networks without the need for crazy energy-intensive schemes such as the proposal to pump water from the River Severn to the Thames. With urban flooding on the increase, research at the University of Exeter has demonstrated that the installation of rainwater reuse can also reduce flooding. The government should mandate rainwater reuse at new developments as RWH represents the ideal solution to these problems.

RWH has provided water to civilisations over thousands of years, and yet it seems to be a forgotten opportunity in the UK. We expect all water we interact with to be fit to drink, and yet only two per cent actually gets drunk. So why does the remaining 98 per cent need to be potable? The phrase “fit for purpose” comes to mind. You wouldn’t serve a can of coke in a crystal flute, so why flush your morning ablutions with pristine drinking water.

The rainwater harvesting solution?

If every house collected roofwater for use in toilets and washing machines, potable supplies could be reduced by 50 per cent. Our reservoirs would never run dry, and perhaps even The River Kennet might experience some natural flow.

With unsustainable abstraction rates, alternative water supply options must be implemented, otherwise, the south east of the UK will run out of water in the decades ahead. It’s not just common sense to flush with rain, it’s a solution to a problem that frequently raises its ugly head over the horizon. However, government policy is a slow moving beast and it is evident that the complex needs for sustainable technology delivery are mired in murky incentive mechanisms such as the Feed in Tariff.

In recent years, the government has provided a range of costly subsidies for photo-voltaics and so-called property level flood protection. Conversely, mandating sustainable practices such as rainwater reuse is a low-cost approach and the economic benefits would be widespread as the industry would boom and employment would grow. It wouldn’t cost the government a penny, but it would generate millions in tax income. The mandatory use of RWH works in Belgium, so why do we lag behind here in the UK?

A water butt is a good way to start harvesting water.

A water butt is a good way to start harvesting water. Image by Peter Melville-Shreeve

You won’t be surprised that it comes down to cold hard cash. Even in the south west where water rates have reached £5 per thousand litres, water is a cheap resource. We simply do not pay the true cost of water, as the environmental damage associated with over use is not included in the price we pay. Water companies are incentivised to sweat their existing assets and defer upgrade expenditure. A ticking time-bomb some say? The price of water must more accurately incorporate the wider environmental and asset replacement costs to enable a natural incentive for people to stop flushing drinking water. Forward thinking policymakers would take action now to relieve pressure on the water networks before the camel’s back is broken.

The time has come for the senior ladies and gentlemen of government to stir into action and mandate rainwater reuse. After all, it will help stop flooding, prevent drought and leave our green and pleasant land as just that. The solution’s been here since year dot… it’s time for policy to fall into line. So I say, “Wake up Old Man… it’s raining outside and we are offering you a free umbrella”.

Peter Melville-Shreeve, BSc, MSc, Stream Research Engineer, Centre for Water Systems. Sustainable Water Management Researcher. Contact: .

Peter wishes to acknowledge the generous support from Professor David Butler and Dr Sarah Ward in the delivery of his current research projects.

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