Charged Drainage System

Thanks to SaveH2O, of Supadiverta

This diagram indicates a charged drainage system. These are sometimes called either a “wet” or a “pressure” system.

Charged  Drainage

With this type of system a section of the pipe always remains full unlike a Conventional System.

As the pipes are under pressure it is essential all the joints in above ground and underground pipework are fully watertight


  • A neater appearance than having pipes above ground.
  • Allows you to discharge water at a height above the ground level at the down pipe.


  • It is more likely to block as the flow through the pipes can be fairly slow and the low points can collect silt. Silt will get deposited at flow rates below 0.6m/sec which will be the situation for most rainfall events.
  • It is also more difficult to unblock.
  • Can cost more with excavation and additional inspection fittings .
  • Potential for mosquito  breeding  in water unless appropriate screes are installed.


Also see Underground Pipes



  1. karen

    As a newbie to rain collection, I am always searching online for articles that can help. Thank you

  2. Rolf

    magnificent post, very informative.

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