Homebuyer Flood Risk Reports

At FPS Environmental Ltd, we provide expert flood risk consultations and property surveys aligned with the CIRIA C790 Code of Practice. Our work focuses on identifying risk and providing clear due diligence before a purchase. Whilst this typically involves two stages, the scope is bespoke and depends on the property, the available information and the level of risk identified.

Stage 1: Detailed Flood Risk Assessment

This service is different from a Flood Risk Assessment for Planning Applications, which is required to support development proposals.

Objective: To deliver a comprehensive property-level flood risk study.

Activities Include:

• Analysing Environment Agency/ Natural Resources Wales/ SEPA flood mapping in relation to your property’s layout and topography.
• Utilising LiDAR data for an accurate understanding of ground levels, should topographical survey data be unavailable.
• Obtaining river model data (Product 4 or Product 6) and analysing predicted flood levels, depths and flow routes in relation to the site.

• Producing detailed GIS mapping to analyse surface water flood risk, flow routes and local topography.

• Understanding existing flood management measures and reviewing area-wide Strategic Flood Risk Assessments along with historic flood data.
• Where available, we review drainage records such as a CON29DW Report to understand how the property connects to the wider drainage network.

Stage 2: Site Survey

Objective: To evaluate the property and its flood risk, guiding the selection of appropriate mitigation options (if necessary), such as Property Flood Resilience, or strategic recommendations including drainage, landscaping & walls (inclusive of what consents may be required).

Activities Include:

• Conducting a property-focused site visit, complemented by a broader site walkover to align flood risk modelling with actual conditions.
• Understanding the mechanism of flood events and how these may impact the property.
• Reviewing and recording the property’s construction and drainage (where accessible) to understand flood event mechanisms, potential water ingress points, and existing mitigation measures.
• Digitally recording on FPS software critical data such as aperture dimensions and identifying areas for potential risk reduction.
• Preparing a floorplan with routes of ingress marked.
• Identifying any visible existing mitigation measures in place.

This thorough approach ensures you receive a detailed understanding of your property’s flood risk, enabling informed decision-making from a risk of flooding.

In some circumstances CCTV Drainage Surveys can be a valuable part of the flood risk due diligence process.

For all heritage properties we recommend a CCTV survey prior to any purchase so the condition and layout of the drainage system is understood. Older drainage infrastructure is often poorly documented and defects such as collapsed pipes, root ingress or misconnections can influence flood risk and property condition.

Drainage surveys can also be necessary where mitigation measures are being considered. Understanding the existing drainage network is important when developing options such as backflow protection or pump systems.

For modern managed developments, such as leasehold flats, it may also be possible to request drainage information during the conveyancing process. This is sometimes retained within the CDM file or building management records and can provide useful insight into how well the drainage infrastructure has been maintained.

Our reports can help you fully understand the flood risk associated with your new home, how your home insurance relates to flood risk and how you can best protect your future home.

You can check if your new home is in a flood risk area here, or you can contact your local planning authority to check if your home is in an area previously identified as having a critical drainage problem or historic flooding.

The freely available flood maps are limited in resolution and may not accurately reflect on-site conditions. They often overlook localised drainage connections and whether a property is elevated above flood levels. Therefore, it’s crucial to have a Flood Risk Consultant visit the site to assess the actual flood risk to the property as thoroughly as possible. This assessment enables you to make an informed decision about your property purchase.

Fees

Our due diligence Homebuyer Flood Risk Report is for clients looking for a detailed interrogation of available flood risk data, coupled with a site assessment.

Fees depend on the size and scale of the property, the risk, level of assessment required, and distance from our most suitable Flood Risk Consultant. As a guide, assessments typically start from around £2,000+VAT.

Homebuyer Flood Risk Report

A Homebuyer Flood Risk Report is aimed at people purchasing a property. It provides due‑diligence on the flood risk for a specific address. The assessment reviews flood mapping, historic flood records and on‑site conditions to understand how water may affect the building. It also outlines what this could mean for insurance, resale value and the long‑term resilience of the property. Where relevant, it takes climate change into account by reviewing available data or catchment behaviour. If a flood risk is identified, the report may identify possible mitigation options where viable, for the buyer to consider.

Flood Survey

A Flood Survey is slightly different. Flood surveys are usually carried out after a property has flooded or where a clear risk already exists. The purpose is to understand the mechanism of flooding affecting the building and to identify practical ways to manage the current risk. While it includes a risk assessment, the emphasis is on how to reduce the impact of flooding on the existing structure. The mitigation recommendations from a flood survey can be developed further if needed. This is done through Options Development and Design work, for example where a new drainage system is proposed or where a flood wall may be appropriate. In these instances, the initial findings from the survey can be taken further and developed into practical design solutions specific for the site or property.

Flood Risk Assessment for Planning

If on the other hand, the intention is to develop land or submit a planning application, this requires a 3^rd type of activity, a Flood Risk Assessment for Planning (FRA). FRAs are prepared to support the planning process and to demonstrate to the local authority that the proposed development will be safe from flooding and that will not increase flood risk elsewhere.

You can learn more about:

• Flood Surveys
• Flood Risk Assessments for Planning Applications
• Options Development & Design

Flooding can happen at any time and at varying degrees of severity. Around 5.2 million homes in England, or one in six properties, are deemed at risk from flooding. Surface water flooding affects more properties than any other types of flooding, yet the risk is often overlooked.

The FPS Homebuyer Flood Risk Report provides a market leading analysis of flood risk, including a site visit, alongside detailed desktop study and GIS map production.

There are many factors that can affect the extent and impacts of flooding that may be experienced and are why it is vital to obtain a more detailed study.

A Forensic Approach to Property Flood Risk

Many flood reports produced for property purchases are largely template based or automatically generated from national datasets.

Our approach is different.

In many respects the process is closer to forensics than reporting. The question is not simply whether a flood risk appears on a map, but what evidence exists, whether it aligns with the site conditions, and how flood water would likely interact with the site and property, depending on the topography, drainage, and construction.

We interrogate the available data and review the property itself. We look to ascertain what information exists for the catchment, and if that data aligns with what we see on the ground, such as whether the property elevated relative to surrounding land and how flood water might interact with the building during an event.

Where relevant or available we review hydraulic model data, drainage information, soil types and ground permeability, alongside the layout and construction of the property.

The aim is to move beyond a simple “risk flag” and instead understand what the risk actually means for the building being purchased, what mitigation options may exist, and how this could influence practical considerations such as insurance, resilience or future works.

“Flood risk is not simply whether a property appears on a map. The real question is how water would behave at the site, how it might interact with the building, and whether the available data supports that conclusion.”

Simon Crowther BEng (Hons) FCIWEM C.WEM MIET

Director, FPS Environmental Ltd

Riparian Ownership and Watercourses

If the property you are purchasing borders a river, stream or ditch, it is also sensible to ask your conveyancer about riparian ownership and what this may mean for you as the owner.

Riparian ownership can involve certain responsibilities for maintaining the watercourse and managing vegetation or obstructions. In some cases, works to the channel, its banks, or surrounding area may require permissions or Environmental Permits before they can be carried out.

Further information on this topic can be found here:
Understanding Riparian Ownership and Flood Risk