As well as one of life’s “essentials,” water is a crucial element in a variety of industrial processes, not least construction.
To the casual observer, the only visible evidence of construction site water use might be a worker hosing down a truck full of construction waste to prevent the escape of dust.
But lots of water is used in many aspects of construction, and in a variety of ways.
Amid a climate change crisis and the increasing threat—and instance—of drought, the sector is looking at ways to improve water efficiency in construction projects, as well as doing to more to source what it does use responsibly while striving to minimise waste and leaks.
How much water is used in construction?
According to the Construction Products Association, water is used throughout the construction lifecycle, from extracting raw materials, to construction product manufacturing, throughout the building phase, and obviously once buildings have been completed and are occupied.
And when a building has reached the end of its useful life and is set to be demolished, water is used in that process too, not least to reduce the spread of dust and other debris into the air.
The CPA goes on to say that manufacturers of construction products rely on water across a broad spectrum of uses. Water, it says, “can serve as a lubricant, a cleaning agent, a sealant, a heat transfer medium, a solvent, an air pollution control medium, plus an array of other uses depending on the material and products being produced.”
Crucially, water is used in the manufacture of mortar and cement concrete, materials which have their own issues when it comes to energy efficiency and their environmental impact.
According to the journal Nature Sustainability, in 2012 concrete production was responsible for 9% of global industrial water withdrawals and 1.7% of total global water withdrawal.
The UK Centre for Moisture in Buildings reckons that up to 8,000 litres of water may be included in mixtures and materials as construction of an average-sized new-build home proceeds, although this varies depending on the design.
The importance of water management during construction activity
Water is clearly a crucial component of construction activity. Consequently, its sourcing, storage, use and eventual disposal need to be managed effectively.
With mounting pressure on existing water supplies amid threats of droughts and other climate change-related events, having a construction water management plan in place is a must.
There is plenty of information available to the construction sector covering how to use—and conserve—water during project delivery.
In the UK, the Construction Leadership Council has drawn up water management guidance which asserts the need “to improve the efficiency of water use on construction sites through better planning and management … and to encourage consideration of environmental risks associated with construction activities.”
The CLC said its ultimate aim was to eliminate the demand and use of potable water in construction. “It is unlikely that water demand can be eliminated, but efforts can be made to reduce and use alternative sources, as well as reuse water for construction activities,” it added.
Once a project’s water needs had been identified, alternative sources should be planned for, with a metered potable supply available as backup.
The CLC calls for a water use hierarchy to be put in place, addressing—in descending order—the elimination of unnecessary water use; consideration of alternatives to potable water, such as rain and “grey” water; reduced use; and the reuse and recycling of water.
Effective water management is a group effort
The Water Conservancy organisation encourages water conservation at every stage of a construction project, from design to planning and the construction process itself.
It also highlights the importance of involving the people tasked with delivering a scheme in the water use goals.
It is important, it says, to establish water conservation as a key objective of the project and ensure that everyone involved is aware of their responsibilities.
The Water Conservancy adds that induction training should be provided for new employees and contractors, “so that they are also aware of their responsibilities and the benefits of the program,” while the project’s water management plan needs to be kept on site, to “ensure that all employees are aware of and have access to it.”
Water management needed to be discussed at regular meetings, the Water Conservancy says, with ongoing achievements monitored.
And in a nod toward the benefits of highlighting good practice, it adds: “Promote your successes with press releases to local media and industry associations.”
What are the rules and regulations around water consumption?
There are several areas of regulation covering water and the built environment, although these are focused on the degree to which water is used—and saved—once a development has been completed.
The mayor of London’s office spells out how agencies in London and adjoining regional and local planning authorities will work to “protect and conserve water supplies and resources in order to secure London’s needs in a sustainable manner.”
It stipulates that development should minimise the use of mains water by incorporating water-saving measures and equipment and by designing residential development so that mains water consumption would meet a target of 105 litres or less per head per day.
There will also be support for sustainable water supply infrastructure in new developments as part of water companies’ water resource management plans.
How to reduce water consumption in construction: now and in the future
While construction is improving water usage, designers of the homes and other buildings society needs will be creating them with water efficiencies in mind.
Planning authorities want limits of 125 litres of water per person per day on new housing developments as part of the Building Regulations Part G, and can demand a lower limit of 110 litres as part of a planning condition.
The water footprint of a new home or office can be reduced considerably by thoughtful design.
Showers can replace baths, or baths can be designed to be more water efficient. Dual flush toilets are becoming the norm, while rainwater collection, via a water butt system, can replace tap water for most outside uses. Meanwhile, appropriate landscaping can protect homes from flooding—another consequence of climate change—and prevent wasteful water run-off.
With the world on the brink of a full-blown climate crisis, water efficiency in construction must be addressed. The sector is no doubt fully aware that it makes good environmental—and business—sense to tackle the water issue sooner rather than later.