Jean-Yves Gilg

Editor, Solicitors Journal

Sustainable drainage: A tightening regime requiring duty of care

Sustainable drainage: A tightening regime requiring duty of care


GeoSmart Information explains why understanding the site drainage conditions and options for SuDS is essential for solicitors advising developers and landowners

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?

The second priority in the drainage hierarchy is a watercourse. If chosen, this would require the landowner's permission where the watercourse runs through their land - there may need to be an easement to discharge to the watercourse, and there could be nuisance issues if the discharge increases the burden to the downstream owner.

Where this is not possible, discharging to a sewer would be limited to surface water only and not combined or fire sewers.

Meeting duty of care requirements

In common law, clients must be warned of risks that are apparent to the solicitor but not to the client. Therefore, if there is an impact on the viability of a site due to a potential requirement for SuDS, then the solicitor has a duty to advise the client that this is the case. The last thing you will want is for the client get their architect to design a 100-house site only to have 20 taken away to accommodate a SuDS requirement.

The Solicitors Regulation Authority statement of solicitor competence makes clear that the solicitor must advise on relevant options, strategies, and solutions, understanding the client's commercial circumstances, and '[ensure] advice is informed by legal and factual analysis and identifies the consequences of different actions'.

Therefore, it is essential that all available information on site drainage is provided to meet this requirement.

CON 29 revisions

The CON 29 local authority search has recently been revised, with a new set of drainage questions in section 3.3 'Other Matters'. These ask about the presence of SuDS, whether the property is served by them, and who bills the owner for the surface water drainage charge.

Their inclusion by the Law Society is a clear recognition that guidance is tightening around the solicitor's requirement to ask questions about SuDS. However, they do little to tell you what liabilities your client may have and only if SuDS is already there.

Understanding the site drainage conditions and options for SuDS is therefore essential for developers and landowners ahead of submitting a planning application at the pre-planning stage or to address a planning condition prior to permission being granted.

SuDSmart reports from GeoSmart Information can be used to support applications and verify suitable conditions for infiltration drainage on site. They can also identify whether or not your client's site is suitable for SuDS as part of pre-acquisition due diligence.

For a copy of the SuDS guidance for property professionals and to enquire about SuDS suitability reports for your client's site, visit, email, or call 01743 276 150.