How water is supplied to the home
The water supply to most homes in the western world is provided by the local water supply company, through heavy iron or plastic water pipes. From the main, a pipe known as a connecting pipe carries the water to the water company’s tap: a control valve about 1m below ground at or near the boundary of each property. The shut-off tap, which is turned with a long key, is located at the bottom of a protection tube made of earthenware under a small metal cover, embedded in the surface of the garden or in the outside public footpath. On older properties, this may be the only place the water can be shut off. Sandwiched between the outside faucet and the water mains, is the water meter. To avoid frost damage, it should be at least 750mm and no more than 1.35m below ground.
There are two main types of cold water supply to a home: direct and indirect. In a direct cold water supply, branch the pipes from the riser main pipe directly to the cold water taps and WC cisterns in the house. This means that you can drink cold water from any tap. The point from where the service pipe enters the house, usually near the kitchen sink, is known as the riser main. A riser main pipe will usually feed a storage cistern in the loft (the hot water cylinder reservoir). A direct cold water system is easier and cheaper to install than an indirect system.
In an indirect system, which is more common than a direct water system, the main riser feeds the cold faucet in the kitchen sink (and possibly the lines to a washing machine and an outside faucet). The water is clean drinking water. It then continues to the cold water storage tank on the roof, which supplies all the other taps, the toilets and the hot water storage tank. If your home is an indirect system, do not drink the water from any faucet other than the one in the kitchen. Tank water may not be clean.
There are advantages to an indirect system: Water from a cold water storage tank provides even water pressure, leading to quieter plumbing and less wear on washers and valves. Leaks are also less likely, and any leak that does occur will be less damaging than one from a pipe under main pressure. Water from a cistern is warmer than tap water, so less hot water is needed for washing and bathing. It also reduces condensation in toilet tanks. And if the house supply is temporarily cut off, for example for manual labor, there is a stored water supply available for use.
Whether you have a direct or indirect water system, make sure you and others in the house know where the shutoff faucets are, as well as the gate valves on the supply pipes. You should be familiar with this and also label them properly as this will protect you from potential water damage. This information is even more vital when a plumber is not easily accessible in an emergency.
Leave a Reply