The Limits of Current Flood Diagnostics: How to Better Protect Your Property in 2025
Date November 12, 2024 / Reading time: 5 minutes
Why standard property diagnostics don't detect all flood risks
Since 2003, French law has required property owners to provide their buyers and tenants with a diagnostic report detailing the natural and technological risks to which their properties are exposed. This Buyer and Tenant Information (BTI) is an essential element in decision-making when purchasing real estate or renting commercial properties.
According to Article R. 125-24 of the Environmental Code , all owners must indicate whether their property is located in an area covered by one or more natural risk prevention plans (PPRN), specify the status of this PPRN (prescribed, anticipated, approved, or under review) and detail the specific natural risks.
The limits of the Géorisques platform in the face of new climate realities
To carry out this diagnosis, owners are directed to the Géorisques platform ( www.errial.georisques.gouv.fr ), developed by the Ministry of Ecological Transition and BRGM. By simply entering an address, the user obtains a report on potential technological and natural risks.
But this approach has a major flaw: it only takes into account areas officially classified as flood-prone, mainly linked to river flooding and rising water tables.
However, the reality on the ground is quite different. Statistics show that:
• Nearly 10 million jobs in France are located in flood zones
• 92% of municipalities in Île-de-France were subject to at least one natural disaster order for flooding between 1982 and 2021
• 88% of these floods were due to runoff phenomena rather than classic floods
Rainfall runoff: the invisible risk ignored by standard diagnostics
The majority of current flooding is caused by sudden, intense rainfall that generates significant runoff, quickly saturating water drainage systems. These phenomena often affect areas not classified as flood-prone in the PPRN.
This gap creates a dangerous situation where businesses and individuals believe they are protected against flood risks, while remaining vulnerable to these new types of increasingly frequent climatic events.
The financial impacts of an incomplete diagnosis
The increase in natural disasters linked to climate change is already having a direct financial impact on all French people. The Cat-Nat fund, which we all finance indirectly, will see its surcharge increase from 12% to 20% on January 1, 2025 .
Poor risk assessment leads to:
• Costly material damage for businesses and individuals
• Significant operating losses
• Impacts on employment (partial unemployment)
• Excessive use of the Cat-Nat diet
• A general loss of purchasing power
When official diagnosis fails to prevent catastrophe
Let's take the concrete example of a restaurant for which the Géorisques assessment indicated no flood risk. Following a violent storm, the establishment found itself under 80 cm of water, causing considerable damage that the owner had not anticipated.
This case perfectly illustrates the problem: the standard diagnosis was technically compliant with the regulations, but totally unsuitable for new climatic realities.
Climate Performance Diagnosis: an innovative approach to anticipate real risks
To meet these challenges, the Climate Performance Diagnosis (CPD) developed by Tardigrade AI offers a complete assessment of the climate vulnerability of a property.
This innovative solution stands out for:
• Analysis of exposure to around ten climatic hazards, including pluvial flooding
• The use of a digital twin of the land integrating surrounding buildings, the nature of the soil and slopes
• Projections based on IPCC models to anticipate future risks up to 2050
• Precise geolocation of potential water heights
In the case of the restaurant mentioned above, the DPC would have identified a risk of pluvial flooding with a 2% probability of experiencing a water height of 80 cm in the next 20 years.
How to reduce the risk of rainwater flooding
With accurate information on real risks, owners and businesses can put in place effective preventive measures:
• Raise sensitive equipment and machinery
• Avoid storing important products or documents in exposed areas
• Install removable protective devices (cofferdams)
• Preposition evacuation pumps
• In some cases, reconsider the location of a new installation
Conclusion: Anticipate to better protect your assets
The climate is changing, and our risk assessment methods must evolve accordingly. A static assessment based solely on PPRNs no longer allows us to effectively anticipate current and future climate risks.
As a business owner or manager, you can't stop the rain from falling, but now you can rely on tools like Tardigrade AI DPC to protect your assets, your work tools, and your employees' jobs.
FAQ: Flood Diagnostics and Protecting Your Property
What is a stormwater flood?
A runoff flood occurs when sudden, intense rainfall cannot be absorbed by the ground or carried away by drainage systems. The water then flows over the surface, potentially causing flooding even in areas not near waterways.
What is the difference between flooding and runoff flooding?
Flooding by flooding is linked to the overflowing of a watercourse (river, stream) which bursts its banks. Flooding by runoff is caused by intense precipitation which generates surface flow, regardless of the presence of a watercourse nearby.
Why are runoff floods becoming more frequent?
Climate change is leading to an increase in extreme and sudden rainfall events. At the same time, increasing urbanization and soil sealing are reducing natural absorption capacity, exacerbating runoff.
Is a flood diagnosis mandatory when selling real estate?
Yes, since 2003, the Information for Purchasers and Tenants (IAL) has been mandatory and must state whether the property is located in an area covered by a Natural Risk Prevention Plan (PPRN).
What exactly does a standard IAL diagnosis contain?
The standard IAL diagnosis indicates whether your property is located in an area covered by a PPRN, specifies the status of this plan (prescribed, approved, etc.) and details the officially identified natural risks, such as river floods or rising water tables.
Why might the Géorisques diagnosis be insufficient?
The Géorisques diagnosis is based solely on areas officially classified as flood-prone in the PPRN (Regional Plan for Regional Planning and Development), which generally do not take into account flooding caused by rainwater runoff. However, this represents 88% of disasters in the Île-de-France region.
What is the Tardigrade AI Climate Performance Diagnosis (CPD)?
The DPC is an innovative solution that assesses the comprehensive climate vulnerability of a property by analyzing its exposure to around ten climate hazards, including pluvial flooding. It uses digital twins of the terrain and projections based on IPCC models.
How does the DPC differ from the standard Géorisques diagnosis?
Unlike the Géorisques diagnosis, which is limited to officially flood-prone areas, the DPC analyses the relief, the nature of the soil, surrounding buildings and future climate projections to identify all types of flood risks, including runoff.
How do I know if my property is particularly vulnerable to runoff flooding?
Certain indicators may alert you: your property is located at the bottom of a slope, in a natural basin, or in a heavily urbanized area with few green spaces. A Climate Performance Diagnostic will provide you with a precise assessment of this vulnerability.
How to access the Climate Performance Diagnosis?
You can obtain a DPC for your property by contacting Tardigrade AI directly or visiting their website. The diagnosis can be performed on any type of property, whether residential or commercial.
Would you like to get a diagnosis for your business? Contact us today.