Building standards guidance - Section 3.3 Flooding and Groundwater: consultation on proposed updates

Proposed updates to Section 3.3 of the Technical Handbooks

Background

As noted in section 1.1.2, the 2018-19 Programme for Government included a commitment to develop a property flood resilience action plan. This established the Property Flood Resilience Delivery Group (PFRDG), which was tasked with preparing and delivering an action plan to help property owners take action to make their properties more resilient against the impacts of flooding. Influencing policy and providing clear guidance on PFR to industry, property owners and occupiers is a key objective of the PFRDG’s Living with flooding: an action plan for delivering property flood resilience in Scotland.

To support this objective, we are consulting on proposed updates to the guidance published in Section 3.3 Flooding and ground water of the Building Standards Technical Handbooks, including the addition of further flooding advice and information in the form of a new Annex 3.B Building Standards Flood Guide.

Through this consultation we are seeking feedback from users of the Technical Handbooks on whether the draft updated guidance, as set out in full in this consultation paper, provides them with more useful information on how to achieve compliance with Mandatory Standard 3.3. We are also seeking to confirm that the guidance is clear and easily understood.

The outcome of this consultation will inform any amendments to the draft guidance and Annex 3.B, with a view to publishing confirmed changes in updated versions of the Technical Handbooks in early 2026.

Current guidance on flooding and groundwater

Mandatory Standard 3.3 Flooding and groundwater is unchanged and requires that: ‘Every building must be designed and constructed in such a way that there will not be a threat to the building or the health of the occupants as a result of flooding and the accumulation of groundwater’.

Currently, guidance to support compliance with standard 3.3 is set out in Section 3.3 of the Building Standards Technical Handbooks under the following clauses:

• 3.3.0 Introduction
• 3.3.1 Groundwater
• 3.3.2 Flood risk assessment
• 3.3.3 Resilient construction in flood risk areas

Summary of proposed changes to current guidance

Respondents should note the main areas of change proposed are as follows:

• Clause 3.3.0 the introduction to the standard is updated and expanded to give further context to the risks associated with flooding from various sources, the need to assess flood risk and the importance of addressing property flood resilience when developing in flood risk areas. There is greater emphasis on the two actions sought under the standard – flood risk assessment and a property flood resilience response where flood risk is identified and development still takes place.
• Clause 3.3.1 set out expectation on the need to undertake a flood risk assessment for any development site. It expands on previous guidance in clause 3.3.2 and notes the issues to be considered in a risk assessment and provides updated and comprehensive information on where further information can be accessed on how to undertake and report on such an assessment. Specific commentary is also offered to clarify the application of the mandatory standard to work other than new buildings. Current guidance on surface water run-off is also provided.
• Clause 3.3.2 on Groundwater is principally unchanged from current text in clause 3.3.1 on this topic, other than updated references to relevant assessment standards.
• Clause 3.3.3 on delivery of flood resilient construction is significantly expanded upon. Current guidance is short and makes reference to two supporting publications. This amended guidance clause is structured to take the reader through the process of developing a suitable approach to building specification that considers and applies both flood resilience and recoverability options. It notes further sources of information and presents the example of the CIRIA Code of Practice standards. It then presents supporting guidance explaining how those standards can be implemented, following good practice, setting our recommendations for relevant elements of the building construction which could be affected by flooding.
• A new Annex 3B is introduced. This gathers and re-presents information drawn primarily from the previously published Planning Advice Note (PAN) 69 on flood risk. This re-publication is intended to provide background information on the water environment and the factors which contribute to flooding. Its purpose is to raise awareness and knowledge of flood risk and measures to mitigate flooding. It also presents a guide on the interaction of the building standard process with other statutory processes relating to flood risk management.