Growing sustainable trends - water footprinting

No resource is more precious, or taken for granted, than water. While enlightened construction professionals are designing water saving products and systems, and environmental accreditation pushes us towards recycling and water efficiency measures, the water used in the manufacture of everything from bricks to bathroom cabinets and light bulbs is never mentioned.

New perspective

This may sound strange, but how does a lightbulb use water in its production? Water is involved in all aspects of the lamp’s life: think of the extraction of sand to make glass or iron ore to make the screw fitting. This is embedded water and its measurement is akin to that of the embodied energy we already recognise as being used to make, package, transport, install and dispose of, or recycle, a product. In this respect, the amount of water used can be phenomenal.

Water is embedded in absolutely everything. It takes 170 litres to make a pint of beer;10 litres to make a sheet of A4 paper; 2,400 litres to make a hamburger, and a colossal 8,000 litres to make a pair of leather shoes. Imagine the impact of products and processes in the building trade.

“The construction industry is very water dependent,” says Jacob Tompkins, director of Waterwise, a UK NGO focused on decreasing water consumption. “Directly, via material and processes such as water for concrete, water for dust suppression, water for cutting, water for mortars etc; and, indirectly, with embedded water in all construction products.”

“The food, chemicals and household products, power generation and drinks industries are beginning to address embedded water. These are the very few so far but it will become a huge issue.”

"Customers are going to start expecting water efficient buildings and investors are going to expect all companies to have excellent credentials on water waste and energy."

Jacob Tompkins, director of Waterwise

Unfortunately, much of the construction industry isn’t aware of the issue at present. “It is an emerging issue,” says Mark Fletcher, European water business leader at Arup. “While we are very aware of it, embedded or virtual water will start to become relevant in supply chain thinking as awareness of all sustainability issues come to the fore.”

Paul Shaffer, associate at CIRIA, says: “Embedded water in construction is an issue that we’re aware of. We made the point to the DTI some five years ago but they didn’t think it was enough of an issue to act upon. However, it will become an important factor in construction in the near future and we need to collect evidence to see how much of a problem it will be. My gut feeling is that water is being wasted in the construction industry.”

Data from down under

According to Waterwise, the only data currently available is from Australia. A study carried out down under in 2004 found that a typical Australian house represents about 15 years worth of operational water – 15 years of washing, cooking, drinking, cleaning, plant watering, and toilet flushing all embedded in a single home. The study went further, estimating that a kilo of concrete has about two litres of embedded water; a kilo of timber, 20 litres; steel, 40 litres; aluminium, around 88 litres; and plastic, 185 litres.

These figures soon add up when just the quantities of materials used on the average construction project are calculated, let alone those for monumental public works or large scale housing schemes. Just as the energy used directly on a construction site is dwarfed by the embodied energy that goes into producing and installing every product, so the embedded water becomes a major factor.

Industry use

To this end, organisations including Waterwise are calling for us to become aware of and try to reduce our water use. Industrial use accounts for about 20% of water use and so has a significant impact on the planet’s dwindling water resources.

"Embedded water will become an important factor in construction in the near future and we need to collect evidence to see how much of a problem it will be."

Paul Shaffer, associate at CIRIA

“Water is going to become more expensive. There is going to be increased pressure for careful use of water in processes, through regulation, price and availability,” says Tompkins. “Customers are going to start expecting water efficient buildings and investors are going to expect all companies to have excellent credentials on water waste and energy.”

Fletcher says: “The cost of water may not impact on construction in the very near future because it is still relatively cheap compared to other building products. However, people have to start considering better management of their water supplies; recycling and reuse.”

To add a further note of gloom to this already unpromising outlook, the globalisation of trade is directly impacting on countries’ water assets. Water intensive production of foods and other materials that are to be exported from say, India to the UK or US, are directly fuelling chronic droughts in the country: similar water shortages are being reported in China, a major product manufacturer and Kenya, where agriculture is dominant.

Two footprints

“My message is start looking at water now, where and why you use it, how you can cut waste and costs and how you can be more efficient,” says Tompkins. Waterwise is a good first port of call. It has just set up a new organisation in the east of England, called Waterwise East, to work on these issues with developers in the region.”

So, everyone now has two sets of environmental footprints, carbon and water. And, our most precious resource? Forget oil, water is harder to transport and there are no alternatives to it. Water is set to become the world’s blue gold.