Water resources are widely used within the built environment through material use, construction processes and by the end-users of buildings.
The Government has a target of reducing water consumption by 20 per cent per person by 2030. This has been addressed in Part G of the Building Regulations as well as being required in the Code for Sustainable Homes.
The water strategy for England sets out the Government’s plans for water in the future and the practical steps needed to ensure good clean water is available for people, businesses and nature.
The challenges associated with water availability are likely to increase over time, with the impact of climate change - particularly in the south east of England. This is due to increased periods of drought as well as frequency of heavy downpours where much of the water will be lost through surface water run-off from large areas of hard landscaping. Sustainable Urban Drainage Systems (SuDS) are a means of managing surface water to reduce flooding, manage watercourse pollution and enhance biodiversity.
As water becomes scarcer, we will be required to extract water from river-basins which will negatively impact on the ecology and biodiversity of our landscape. Treating water in order to make it drinkable also requires significant amounts of energy use, further contributing to climate change.
City infrastructure is an important aspect for preserving water and managing flooding. Careful planning of green infrastructure can help cities manage large design storm events to prevent issues such as flooding caused by surface runoff, and where it is not possible to prevent flooding, cities must consider resilience strategies to protect vulnerable areas appropriately.
There are a range of measures that can be employed in buildings to reduce the use of potable water, from installing simple water saving devices, to implementing rainwater harvesting, greywater and blackwater recycling and treatment systems. Waterwise have a useful guide to products here.
There are several standards and tools available to measure and reduce water use through building design. The ISO 14046 Water Footprinting Standard was launched in 2014, as well as pre-existing standards and assessment methods by the Carbon Trust’s Water Standard and the AECB Water Standard.
An industry led standard and measurement tool by the Water Footprint Network also exists to aid in measuring the water footprint for different building designs.
Additionally the European Water Label was launched in 2014 to enable comparison of products for water efficiency.
Code for sustainable buildings
In the UK, every person uses approximately 150 litres of water a day, which is a figure that has grown every year by 1% since 1930. If you take into account the water that is needed to produce the food and products individuals consume in their day-to-day life (known as embedded or embodied water) each person actually consumes approximately 3400 litres of water per day.
Water use was recognised as a key issue in the UK-GBC's work on the proposed Code for Sustainable Buildings which we completed in March 2009. The task group recommended that a Code for both new and existing non-domestic buildings incorporate minimum standards on water use performance, which are made increasingly more demanding over time (more information on that task group here).
Carbon related impacts
There is an increasing body of research looking at the carbon impact of water use, in particular hot water use in the home. The Energy Saving Trust estimate that on average, hot water use is responsible for over a fifth of a home's carbon footprint and makes up 5 per cent of the UK's total greenhouse gas emissions. If every UK home reduced their hot water use by just 5 per cent, the CO2 saving would be equivalent to taking nearly 530,000 cars off the roads.
Sustainable Community Infrastructure
The UK-GBC Sustainable Community Infrastructure (SCI) Task Group explored the sustainability benefits of supplying, disposing of and reusing water at community scale. The task group produced a 'decision framework' to help stakeholders assess the potential for community scale water solutions. The group also produced a map of current key policies, legislation and guidance relating to water infrastructure, along with a supplementary policy ‘roadmap' which sets out what is known about the direction of future policy in this area.