Learn about water flow

Flow rate depends on the size of your pipe.

You can only get a certain amount of flow through a small pipe - for example, enough to run one tap. If several taps or appliances are connected to the same pipe there may not be enough water coming through the pipe for all of them. You will then have 'low flow' - perhaps just a trickle of water coming out of the taps.

Years ago, most pipes to houses were half-inch (12.5mm) diameter. Sometimes, a half-inch pipe laid by the landlord or developer was adequate to supply a row or group of houses.

This can often cause low flow problems when occupants draw water at the same time, especially when modern appliances such as dishwashers, washing machines and power showers are used. The first appliance turned on will draw off most or all of the water from the pipe and there will not be enough for any other taps or appliances. 

This can be a particular problem for occupants in converted houses. Generally the ground floor receives adequate flow but higher floors may require the installation of additional pumping arrangements.

Modern houses and flats usually have bigger pipes - 25mm diameter (outside diameter). This means the water flow will be much higher, so there is enough for several appliances to be used at once.