Legislation compelling developers to build sustainable, rather than piped, drainage systems comes into force in October. Here’s how it will work

The provisions of Schedule 3 of the Flood and Water Management Act 2010 relating to the requirement for sustainable drainage come into force on 1 October 2012. The act is intended to address the problem of serious flooding caused by surface water run-off overloading existing drainage systems. During the floods of 2007, this was the cause of the flooding of more than two-thirds of the 55,000 properties affected.

Conventional piped drainage has limited capacity and cannot control pollution. The government instead favours the use of sustainable drainage systems (SuDS), which use techniques designed to mimic surface water run-off from the site as if it was left in its natural state.

In SuDS, surface water run-off is discharged into (in order of preference): the ground; a surface water body; an existing surface water sewer or highway drain; or, where none of these is possible, a combined sewer. Discharge of surface water into a foul sewer is not permitted.

The government estimates the change to SuDS will save £5.1bn a year

The government intends to compel developers to build SuDS by establishing national standards. These have not yet been set but were the subject of a consultation process that ended on 13 March 2012.

Approval of SuDS

The 2010 act removes the existing automatic right to connect to the public sewer system. It creates SuDS approving bodies (SABs) - these being the relevant local authority at unitary or county level.

The SAB is obliged to approve the design, adoption and connection of any new drainage system, in accordance with the new national standards. The national standards will:

  • Reduce damage from flooding
  • Improve water quality
  • Protect and improve the environment
  • Protect health and safety
  • Ensure the stability and durability of drainage systems.

If the new system meets those standards, then the SAB is obliged to adopt it. The costs of adoption will be met by Defra, and the government estimates the change to SuDS will save £5.1bn a year.

Where it applies

The system will apply to any construction work that requires planning approval or “has drainage implications” (which can be a development of as small an area as 100m2).

The government recognises that the SABs need time to resource themselves for their role and therefore it proposes that the system be phased in over three years from the commencement date using existing planning categories. Initially only large-scale major developments (200 houses or more) and major developments (10 houses or more) will be caught. From 1 October 2015 even minor developments (of more than one house) will need to comply.

Also, as part of the transitional arrangements, it is proposed to make the following developments exempt:

  • Those started within 12 months of the commencement date pursuant to earlier planning permissions
  • Those with planning applications submitted prior to the commencement date
  • Those where existing planning permission is subject to reserved matters and where an application in respect of those reserved matters is submitted within 12 months of the commencement date.

Major infrastructure or highway works will be permanently excluded. Additional provisions about the application of the regime to micro-businesses (employing less than 10 people) are being considered.

The government advises developers to have pre-application discussions with the relevant parties so as to help prevent delay and minimise costs.

What it will cost

For the first three years the application fee will be set centrally, with each SAB setting its own fee thereafter. The initial standard fee is £350 together with a sliding scale fee based on development size (from £70 per 0.1ha on small developments reducing to £10 per 0.1ha on larger ones, capped at £7,500).

The SAB may require a non-performance bond as a condition of approval, to be drawn down if the SuDS is not constructed according to the approved proposals or is unlikely to be completed.

Enforcement will be by means of the existing planning regime - containing criminal sanctions for some breaches.

John Adams, senior associate, Herbert Smith