Barry's Introduction to Construction of Buildings, 4th Edition

12Water Supply and Sanitation

To ensure that good standards of hygiene are maintained in and around buildings, it is essential that care be taken when designing, installing and commissioning the services that will be used to supply cold and hot water and to remove our waste (foul) water. The design and construction of the building should consider the ease of installation of water supply services and subsequent ease of maintenance or repair.

12.1 Cold water supply and distribution

Cold water supply

Mains water suppliers, the water undertakers, have an obligation to provide a constant, potable (drinkable) supply of water, for which service, either a water rate is levied or a charge by meter is made, based on the volume of water used. All new premises and an increasing number of existing houses have a water meter fitted to measure water consumption. Water is supplied, under pressure, through pipes laid under streets, roads or pavements. In urban areas, duplicate trunk mains feed street mains. By closing valves, the individual lengths of mains may be isolated for repairs and renewals without interrupting the supply.

Functional requirements

The functions of water supply are to:

• Deliver clean water suitable for human consumption (Fluid Category 1)
• Provide a continuous supply of water at a constant pressure

Water categories and prevention of cross‐connection to unwholesome water

The quality of water is indicated by five fluid categories – the highest, ‘Fluid Category 1’, being ...