Typical water supply system and components

A water supply system is the set of structures that collects, treats, transmits, stores and distributes water to consumers. A typical urban system is shown below.

Schematic diagram

 [Source: river/lake/well]
          |
      [Intake]
          |  raw water main
   [Raw water pumping station]
          |
  [Treatment plant: screen, sedimentation,
   coagulation, filtration, disinfection]
          |
   [Clear water reservoir]
          |
   [Pumping station]  -->  [Elevated service reservoir]
                                   |
                       [Distribution system]
                                   |
                        House connections

Components and functions

• Source: surface water (river, lake, reservoir) or ground water (well, spring).
• Intake works: draw the required quantity of raw water from the source at a level of good quality and keep out floating matter.
• Raw water pumping and transmission main: lift and carry raw water to the treatment plant where gravity is not enough.
• Treatment plant: screening, plain sedimentation, coagulation and flocculation, filtration and disinfection make the water safe and clear.
• Clear water reservoir: stores treated water and works as a buffer between plant output and pumping.
• Treated water pumping station and main: lift water to the service reservoir or directly into the network.
• Service (distribution) reservoir: stores water at a suitable elevation, meets peak demand, fire demand and emergencies, and keeps the pressure uniform.
• Distribution system: the network of main, sub-main and branch pipes with valves, hydrants and fittings.
• Service connections: house connections, public taps and hydrants that deliver water to users.