Question to the Department for Transport:

To ask the Secretary of State for Transport, what assessment her Department has made of the role of (a) drainage and (b) road foundations in the recurrence of potholes.

Local highway authorities have a duty under Section 41 of the Highways Act 1980 to maintain the highways network in their area. The Act does not set out specific standards of maintenance, as it is for each individual local highway authority to assess which parts of its network need repair and what standards should be applied, based upon their local knowledge and circumstances.

Although the Government does not monitor the frequency of potholes caused by suspected drain related instances, it does encourage authorities to maintain their drainage assets through guidance.

For example, the Pothole Guide (2019), commissioned by the Department for Transport and produced by the Association of Directors of Environment, Economy, Planning and Transport (ADEPT), set out that avoiding water penetration into the road surface is of paramount importance in preventing pothole formation, and that “keeping highway drainage systems working as effectively as possible is therefore a key area of maintenance activity.”

Further guidance on asset management for local highways authorities can be found in the Code of Practice for Well-Managed Highways Infrastructure. This states that “drainage assets should be maintained in good working order to reduce the threat and scale of flooding. Particular attention should be paid to locations known to be prone to problems, so that drainage systems operate close to their designed efficiency.”