Comprensione dell'approvvigionamento idrico: come arriva ai tuoi rubinetti


Translating…

We all use approximately 35 gallons (160 litres) of water a day and we usually take this for granted. It is only during any extended dry spell that we really become conscious of the need to save water and try to use a little less.

Water is supplied by the local utilities / water authority from reservoirs which are filled by rainfall, either directly or from streams or rivers, or even pumped from underground wells. To ensure that the water has enough ‘head’ to create sufficient pressure for the water to flow along the mains the supply point (reservoir) needs to be higher than any of the properties it is intended to supply otherwise it will need to be assisted by being pumped.

The water authority will ensure that this supply is potable (drinkable) and that all nasty trace elements have been filtered out. They usually do this by filtering through sand and pebble beds. Chlorine may be added and in some areas Fluoride is also added for dental protection.

This water is then distributed through a system of pipes (mains), initially ‘trunk mains’ which can be up to 24″ in diameter, and then splitting into sub mains. The sub main pipes are the ones that run under the streets and are tapped into to supply the water to your own home through a pipe known as a rising main. There is usually a stop tap on this supply shortly after it enters your property and this will enable you to switch off the supply of any water entering your property and is probably the most important tap in the house.

There are generally two ways the water then gets to your taps:-

Direct water supply. This is where all taps are fed directly off the rising main and spurs from the main supply feeding each tap in the property. The supply to the kitchen sink should always be fed directly from the rising main to ensure that the water is potable as once it has been stored it is no longer recommended or safe for drinking

Indirect water supply. This is where the rising main feeds a water tank, usually in the roof cavity or attic to ensure that there is enough head pressure to feed all the taps in the property and stored until it is required at your taps. Some of this water will be used to supply a separate tank or cistern for your supply of hot water and some will be piped to your cold taps. A further supply tank may be used to supply water for your heating system or the heating system may draw directly from your cold water cistern.

This is basically how water gets to your taps, allowing you to have a good clean supply of a very basic essential.