The built environment plays a key role to water efficiency. As areas get more urbanised, the water demand increases, especially during hot periods when water is limited. This, over the time has led to the creation of an artificial water cycle which affects the local drainage pattern and other hydrological features. It also increases the need to get water from other resources. According to the same article by Guardian, "The UK has become the sixth largest net importer of water in the world [...] Only 38% of the UK's total water use comes from its own resources; the rest depends on the water systems of other countries, some of which are already facing serious shortages" (Felicity, 2008). This has also an indirect impact on the environment since treating and distributing water requires energy resources which emit carbon dioxide. Moreover, one of the most crucial effects of the built environment in the water cycle is the prevention of natural soak away and the runoff of water, which increases the risk for flooding. A study contacted by Samuel D. Brody et al to identify the impact of the built environment on flood damage in Texas, USA concluded that damages caused by floods is not only because of the rainfall but also because of human development (Brody, Zahran, Highfield, Grover, & Vedlitz, 2007). Hence, in order to improve water efficiency, water management is mandatory.
A way of successfully managing water is to adopt environmental assessment methods. These can be distinguished into two categories: the mandatory and the voluntary. The Building Regulations, which were made a legal requirement by the Building Act in 1984, are a compulsory method. They are formed to ensure the health, safety, welfare and convenience of people in and around buildings and apply to most new and many existing buildings. However they only cover basic performance standards and not the quality of construction. Water efficiency is part of the Approved Document Part G. In the 2009 revised version it is stated that