On and Off-Mains Drainage Systems

Drainage is not a very glamorous topic to talk about, but it is a very important topic. All buildings, if they are residential, commercial or industrial, will have a drainage system in place to service the property’s needs.

It can be either a off-mains drainage system or connected to the main sewer.

To talk to our dedicated drainage team, give us a ring on 0870 863 0123

There are both off-mains drainage systems and on-mains drainage systems:

  • When a building is connected to the main sewer which is owned by your LWA, the waste will leave your property and flow through your pipework before joining into the public sewer before being taken away to be treated.

  • An Off-mains drainage system will be used when connecting to the public sewer is not an option. The system will comprise of several components (typical examples are septic tanks, treatment plants and soakaways) these will treat the waste, before it is discharged into the ground or water course.

Where possible building control recommend connecting to the public sewer, as opposed to having an off-mains drainage system. The good news though is that Below Ground Solutions are experts at working with both off-mains and on-mains drainage systems.

There are several key points to think about when it comes to drainage systems:

  • It is not always feasible to opt for an off-mains drainage system.

  • An off-mains drainage system requires routine maintenance (as per manufacturer’s recommendations).

  • It is not always possible to connect to the public sewer.

  • It is possible to fix a damaged drain, in fact in most cases it won’t cost as much as you might think.


Below Ground Solutions have been servicing the drainage industry for many years building up a wealth of information and experience. We have tackled drainage jobs across the UK in some of the most challenging situations and environments. If you would like to look at some of the drainage works that we have carried out then take a look at our recent jobs page.

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Alternatively, give our specialist drainage team a call today on 0870 863 0123.