Sustainable drainage: A tightening regime requiring duty of care

The Flood and Water Management Act 2010 sought to enshrine sustainable drainage systems (SuDS) and national standards for drainage across both new and existing property. This was replaced in 2012 by the National Planning Policy Framework (NPPF), which has now established consistent rules for drainage on major developments.

The NPPF states that for developments of ten dwellings or more, developers must ensure that SuDS are put in place, unless demonstrated to be inappropriate. Your client may view this and think that if they have to sacrifice 20 houses to accommodate SuDS, then it is inappropriate.

From the policy wording, they must 'demonstrate' this, and therefore there must be a technical reason why SuDS cannot be installed.

Your starting point with your client is to ensure that they effectively research the site geology and prevailing SuDS planning requirements in order to comply.

The recently published guidance note for lawyers is clear about the need to examine the local planning policy and advise the client on how this should be complied with.

These policy standards are becoming increasingly enshrined in SuDS planning conditions by local authorities. Here's an example from South Cambridgeshire District Council: 'The development hereby approved shall be carried out in accordance with the details submitted in the SuDS Management Plan (Author and Date) approved by Anglian Water, submitted with the planning application. The development shall be maintained in accordance with the Management Plan thereafter. (Reason: To ensure that the measures to mitigate flood risk on the site once the development has been completed are fully implemented and maintained, in accordance with policies NE/9 and NE/11 of the adopted South Cambridgeshire Local Development Framework Development Control Policies DPD and the NPPF).'

SuDS management

The SuDS management plan should clearly state how a developer is going to maintain the SuDS (e.g. the cutting of grass, dredging of ditches, maintenance of any pumps, etc.), who does the work, and who is going to pay for it.

The Rentcharges Act 1977 makes provision for limited covenants for the provision of services for the benefit of land management (see Smith Brothers Farms v The Canwell Estate Company [2012] EWCA Civ 237). A development could therefore reasonably create an estate rentcharge for the ongoing maintenance costs associated with the SuDS as part of the management fees or committee responsibilities within the covenants on houses bought on site.

Follow the drainage hierarchy

For minor developments of up to ten dwellings, part H2 of the Building Regulations 2000 applies. A hierarchy of drainage must be followed, where a rainwater soakaway is the first priority, meaning SuDS. H2 states that this should be reasonably practical, and so the same technical, not economic, argument applies: what is the soil geology and how can my client demonstrate they have reviewed the options?