Le Pradet: Clay Soil, Subsidence and Cracks – Official Data

The official exposure to clay shrink-swell (RGA)

The GéoRisques platform (BRGM) classifies Le Pradet at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the benchmark level used by insurers and notaires to assess the risk on a plot. Worth noting: radon potential class 3 across the commune (IRSN/GéoRisques data) – a health-and-building watch point in the affected zone.

This classification completes the decree history above: the hazard rating says what can happen, the decrees say what has already happened. A house rated “high exposure” that has come through one or more dry summers carries a risk of damage that is all the better documented.

What the official clay mapping says

The GéoRisques platform (BRGM) classifies Le Pradet at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the benchmark level used by insurers and notaires to assess the risk on a plot. Worth noting: radon potential class 3 across the commune (IRSN/GéoRisques data) – a health-and-building watch point in the affected zone.

This classification completes the decree history above: the hazard rating says what can happen, the decrees say what has already happened. A house rated “high exposure” that has come through one or more dry summers carries a risk of damage that is all the better documented.

Is Le Pradet in a clay zone? What GéoRisques says

Yes: the GéoRisques platform (BRGM) classifies Le Pradet at high exposure to clay shrink-swell (RGA), with some sectors at medium exposure. This is the reference insurers and notaires consult before any transaction – check it yourself on georisques.gouv.fr by entering the property’s exact address. Another point to watch if you live or are buying here: the commune is at radon potential class 3 (IRSN/GéoRisques), which justifies a measurement in ground-floor living rooms.

This classification and the decree history below complement each other: the hazard rating says what can happen, the decrees say what has already happened. If your house is at high exposure and has come through one or more dry summers, the risk of damage is no longer a hypothesis.

Le Pradet facing drought: what the decrees and the rain tell us

Le Pradet combines a clearly identified clay soil and a substantial Cat Nat record: the GASPAR database records 9 drought prefectoral decrees (full list below) and 12 flood decrees, i.e. 21 natural disaster declarations (Cat Nat). On the weather side, the finding matches: two dry years back to back (2020, 2022), then an abrupt catch-up in 2024 at 898 mm (+29%) – exactly the scenario that puts foundations under strain on the heights between Hyères and La Garde.

Cassini Expertise, an independent building expert, handles cracks and drought-related damage in Le Pradet and more widely across the Var. This page brings together the official data specific to the commune, with no commercial slant.

The Cat Nat history of Le Pradet, decree by decree: to be checked before buying

According to GASPAR, the database listing decrees published in the Journal officiel since 1982, Le Pradet totals 21 natural disaster declarations. Before signing a preliminary contract, ask the seller or the notaire whether the property was the subject of a declaration during one of these periods:

• 9 drought prefectoral decrees (differential ground movement linked to clay shrink-swell (RGA))
  • event of 01/05/1989 (prefectoral decree of 05/01/1994)
  • event of 01/01/1993 (prefectoral decree of 18/07/1995)
  • event of 01/01/1995 (prefectoral decree of 29/12/1998)
  • event of 01/09/1998 (prefectoral decree of 12/03/2002)
  • event of 01/01/2002 (prefectoral decree of 25/08/2004)
  • event of 01/07/2016 (prefectoral decree of 25/07/2017)
  • event of 01/07/2017 (prefectoral decree of 18/09/2018)
  • event of 01/07/2019 (prefectoral decree of 29/04/2020)
  • event of 01/04/2022 (prefectoral decree of 03/04/2023)
• 12 flood prefectoral decrees and storm

Each drought decree frames a precise period: if your house’s damage can be tied to one of them, natural disaster declaration (Cat Nat) compensation is conceivable (provided you declared within the deadlines). If the house was cracked outside these periods, keep the file anyway: it will feed a claim against the seller, for hidden defect (vice caché) or for fraud (dol).

Rain, the real trigger of ground movement

Annual rainfall recorded on the Le Pradet weather grid (Open-Meteo data):

• 2019: 867 mm · 2020: 475 mm · 2021: 753 mm · 2022: 578 mm · 2023: 611 mm · 2024: 898 mm
• Average over the period: 697 mm/year, driest year: 2020 (475 mm)
• Two years of marked deficit: 475 mm in 2020, 578 mm in 2022
• Then a surge in 2024 to 898 mm (+29%)

Shrink-swell plays out in two stages: the drought dries out the clay at depth, it shrinks and the first cracks appear; then the return of the rain rehydrates the ground at a stroke, which swells again and triggers differential movement. The 1970-2000 villas, built on shallow foundations, take the first hit, often 12 to 24 months after the episode. A useful marker: if your house dates from that period and a crack appears one to two years after a dry summer, the causal link is plausible.

Soil and building specifics in Le Pradet

In Le Pradet, we regularly work on villas built between the 70s and the 90s, Provençal or more modern, spread between the wooded heights of Le Pradet (neighbourhoods such as Cannier or the approaches to the Montrodat massif, planted with pines and oaks with water-hungry roots) and the lower areas towards the coastal plain. This hillside configuration creates strong soil heterogeneity within a single plot, often sandy-clay at depth, which encourages differential settlement when the foundations – shallow, as was the practice when these houses were built – rest on ground that does not behave evenly. The estates developed on slopes, with fill sometimes poorly controlled to create buildable terraces, add a further vulnerability: the brought-in soil reacts differently from the natural ground during the clay’s shrink-swell cycles. We also observe that the dense presence of maritime pines immediately next to homes aggravates the phenomenon during drought, their roots drying out the soil beneath the foundations and intensifying the movement. The many renovations and extensions carried out on this older stock, without always upgrading the existing foundations, also create points of differential stiffness conducive to cracking, notably at corners and at the junctions between the original building and the extension.

Drought in the rear-view mirror: 35 years of measured rainfall

The area’s weather archives cover 35 complete years (1991-2025). The driest ever recorded: 2007, with 407 mm over the year, against a local average of 705 mm. 2022 ranks as the 12th driest year out of 35 (578 mm against an average of 705 mm); 2023 follows in 15th place (611 mm).

This ranking gives the true measure of the recent sequence: when the years 2020-2023 sit high up the list of dry years, the clay has had no time to rehydrate between episodes – the textbook scenario for delayed cracking. The reverse is just as instructive: a very wet year following an exceptional drought triggers abrupt swelling of the ground.

Le Pradet: 21 Cat Nat prefectoral decrees since 1982, in chronological order

Each line = an event recognised by an interministerial decree published in the Journal officiel (GASPAR database):

• 🔴 05/1989 → 12/1992 – Drought – clay shrink-swell (RGA) (prefectoral decree of 05/01/1994)
• 🔴 01/1993 → 12/1994 – Drought – clay shrink-swell (RGA) (prefectoral decree of 18/07/1995)
• 🔴 01/1995 → 08/1998 – Drought – clay shrink-swell (RGA) (prefectoral decree of 29/12/1998)
• 🔴 09/1998 → 12/1998 – Drought – clay shrink-swell (RGA) (prefectoral decree of 12/03/2002)
• 🔴 01/2002 → 09/2002 – Drought – clay shrink-swell (RGA) (prefectoral decree of 25/08/2004)
• 🔴 07/2016 → 12/2016 – Drought – clay shrink-swell (RGA) (prefectoral decree of 25/07/2017)
• 🔴 07/2017 → 12/2017 – Drought – clay shrink-swell (RGA) (prefectoral decree of 18/09/2018)
• 🔴 07/2019 → 09/2019 – Drought – clay shrink-swell (RGA) (prefectoral decree of 29/04/2020)
• 🔴 04/2022 → 06/2022 – Drought – clay shrink-swell (RGA) (prefectoral decree of 03/04/2023)

Expert reading: 9 droughts and 12 floods. Clusters (several decrees close together) flag up crisis periods – the summer of 2022-2023 is the best recent example. An owner whose damage dates from a covered period has a solid Cat Nat file; outside a covered period, the way forward is an action against the seller.

The complete chronology of the 21 natural disasters recognised in Le Pradet

Each line = an event recognised by an interministerial decree published in the Journal officiel (GASPAR database):

• 🔵 09/1982 → 09/1982 – Floods (prefectoral decree of 24/12/1982)
• 🔴 05/1989 → 12/1992 – Drought – clay shrink-swell (RGA) (prefectoral decree of 05/01/1994)
• 🔴 01/1993 → 12/1994 – Drought – clay shrink-swell (RGA) (prefectoral decree of 18/07/1995)
• 🔴 01/1995 → 08/1998 – Drought – clay shrink-swell (RGA) (prefectoral decree of 29/12/1998)
• 🔴 09/1998 → 12/1998 – Drought – clay shrink-swell (RGA) (prefectoral decree of 12/03/2002)
• 🔴 01/2002 → 09/2002 – Drought – clay shrink-swell (RGA) (prefectoral decree of 25/08/2004)
• 🔵 12/2008 → 12/2008 – Floods (prefectoral decree of 30/11/2010)
• 🔵 11/2011 → 11/2011 – Floods (prefectoral decree of 21/12/2011)
• 🔵 10/2012 – Floods (prefectoral decree of 20/02/2013)
• 🔵 05/2013 – Floods (prefectoral decree of 29/07/2013)
• 🔵 09/2014 – Floods (prefectoral decree of 04/11/2014)
• 🔵 10/2014 – Floods (prefectoral decree of 04/12/2014)
• 🔵 11/2014 – Floods (prefectoral decree of 03/03/2015)
• 🔵 12/2014 → 12/2014 – Floods (prefectoral decree of 03/03/2015)
• 🔴 07/2016 → 12/2016 – Drought – clay shrink-swell (RGA) (prefectoral decree of 25/07/2017)
• 🔴 07/2017 → 12/2017 – Drought – clay shrink-swell (RGA) (prefectoral decree of 18/09/2018)
• 🔴 07/2019 → 09/2019 – Drought – clay shrink-swell (RGA) (prefectoral decree of 29/04/2020)
• 🔵 10/2019 – Floods (prefectoral decree of 12/12/2019)
• 🔴 04/2022 → 06/2022 – Drought – clay shrink-swell (RGA) (prefectoral decree of 03/04/2023)
• 🔵 08/2022 – Floods (prefectoral decree of 23/08/2022)
• 🔵 09/2022 – Floods (prefectoral decree of 16/10/2022)

Expert reading: 9 droughts and 12 floods. Clusters (several decrees close together) flag up crisis periods – the summer of 2022-2023 is the best recent example. An owner whose damage dates from a covered period has a solid Cat Nat file; outside a covered period, the way forward is an action against the seller.

Damp, water ingress and rising damp in Le Pradet

Damp in a wall can have four causes – rising damp, water ingress, condensation or a leak – and the treatments are completely different depending on the origin.

You have a stain, a smell, blistering render in Le Pradet, and you are looking for a solution. Before signing anything, one essential point: these four causes are treated in completely different ways, and getting the diagnosis wrong means paying for a pointless treatment that will solve nothing.

The 4 causes and how to recognise them

• Rising damp: moisture rises from the ground into the walls by capillary action. It affects the bottom of the walls, often up to 1 m high, with “halo”-shaped marks, efflorescent salts, crumbling render. Common in the older houses of Le Pradet with no damp-proof course.
• Water ingress: water enters from outside (cracked façade, roof, terrace, gutter). The stains follow a specific entry point and worsen after rain.
• Condensation: linked to a ventilation or insulation defect. It appears at cold points (corners, behind furniture, bathroom) and is often accompanied by black mould.
• Leak: a pipe, drain or buried run. The stain is localised, sometimes linked to use (after a shower, a washing machine), and can evolve independently of the weather.

The trap of the diagnosis sold by the treatment contractor

Many companies selling resin injections or drainage systems offer a “free quote”. The problem: they have a direct commercial interest in concluding it is rising damp, since that is the treatment they sell. Frequent outcome in Le Pradet: costly injections installed on a wall actually suffering from a simple leak or a ventilation defect, with the damp returning a few months later.

An independent diagnosis, with no sale of works behind it, identifies the true cause before money is committed. For a neutral opinion in Le Pradet, you can contact us. To go further, read our damp guide for 06, 83 and 13.

Cracks in Le Pradet: the signs that should make you call an expert

• A stair-step crack, passing through the wall, open by more than 2 mm
• A crack that evolves over time (fit a tell-tale – a thin band of plaster or a glass tell-tale – and monitor it for several months)
• Damage that goes with it: doors and windows sticking, tiles splitting diagonally, render bulging
• A house built on clay, a tree close by, drainage that no longer does its job

With 9 drought prefectoral decrees already recognised in the commune, a combination of several of these signs justifies a survey before any repair – and before signing anything, whether buying or selling. Do not fill an active crack before having it recorded: you would erase the proof.

Cracked house in Le Pradet: what to do when buying or selling?

With so many recent decrees and transactions underway, properties change hands every year with damage kept quiet. If you discover cracks after the purchase, two legal levers are possible:

• Hidden defect (article 1641 of the Code civil): serious cracks, invisible at the viewing, predating the sale → price reduction or cancellation, to be claimed within 2 years of discovery
• Fraud (dol) (article 1137): the seller knew and said nothing → cancellation and damages, 5-year deadline; the commune’s GASPAR decree then helps underpin the file

To pursue either of these routes, appoint a property-law solicitor (avocat) – the building survey documents the date and origin of the damage, it does not rule on the law.

How a drought/clay survey unfolds in Le Pradet

• On-site visit: crack survey and classification, crack-width measurements, associated functional damage
• Context analysis: clay nature of the soil, the commune’s Cat Nat record (9 drought decrees), local dry spells
• Works estimate: underpinning, injections, drainage – with several costed scenarios
• A written report, directly usable by the insurer or the solicitor

Independent expert, with no ties whatsoever to any building contractor. Request a visit in Le Pradet – also worth reading, our complete RGA and Cat Nat guide for 06, 83 and 13.

Soil surveys on clay ground: what the regulations say

The requirement for a prior geotechnical survey has applied since 1 October 2020 (ELAN law, art. 68); the new exposure map of 1 July 2026 widens its scope. This obligation, stemming from ELAN law no. 2018-1021, article 68 (decree no. 2019-495 of 22 May 2019), applies particularly to Le Pradet (high exposure in the BRGM classification).

• What it changes for building: the soil survey is no longer an option – the ELAN law makes it compulsory in an exposed zone for every sale of building land and every construction contract. Adapted foundations, ground treatment, drainage arrangements: the specifications flow directly from the survey.
• What it changes when buying a recent property: ask whether the survey was carried out and which specifications were applied. A house built without following the geotechnical recommendations on clay soil is a medium-term cracking risk.
• What it changes when selling: the absence of a survey on a property built before the obligation is not a defect in itself – but if damage appears, a seller who knew about it and concealed it exposes themselves to an action for fraud (dol).
• The link with the data above: Le Pradet combines high exposure with a well-documented history of drought decrees. Building or buying here without checking the nature of the ground means building on a known and measured risk.

Cassini Expertise handles these files: compliance checks between geotechnical specifications and execution, damage surveys on clay ground, counter-expertise. Request a consultation.

Soil surveys on clay ground: what the regulations say

The requirement for a prior geotechnical survey has applied since 1 October 2020 (ELAN law, art. 68); the new exposure map of 1 July 2026 widens its scope. This obligation, stemming from ELAN law no. 2018-1021, article 68 (decree no. 2019-495 of 22 May 2019), applies particularly to Le Pradet (high exposure in the BRGM classification).

• What it changes for building: the soil survey is no longer an option – the ELAN law makes it compulsory in an exposed zone for every sale of building land and every construction contract. Adapted foundations, ground treatment, drainage arrangements: the specifications flow directly from the survey.
• What it changes when buying a recent property: ask whether the survey was carried out and which specifications were applied. A house built without following the geotechnical recommendations on clay soil is a medium-term cracking risk.
• What it changes when selling: the absence of a survey on a property built before the obligation is not a defect in itself – but if damage appears, a seller who knew about it and concealed it exposes themselves to an action for fraud (dol).
• The link with the data above: Le Pradet combines high exposure with a well-documented history of drought decrees. Building or buying here without checking the nature of the ground means building on a known and measured risk.

Frequently asked questions

Is Le Pradet really exposed to clay risk?

Yes. The département is widely affected by the clay shrink-swell (RGA) hazard, mapped by the BRGM and viewable on georisques.gouv.fr. In Le Pradet, the 9 drought decrees recognised in GASPAR leave no doubt: the risk is concrete, not theoretical.

Can a cracked house in Le Pradet be compensated under the natural disaster scheme?

Only if the damage falls within a period covered by a decree (the latest recognised: 1994, 1995, 1998, 2002, 2004, 2017, 2018, 2020, 2023) and if the declaration was made within 30 days. Outside these cases, the action against the seller remains – and it is then the precise dating of the damage by an expert that becomes decisive.

Can the figures on this page be checked independently?

Yes: the decrees come from the GASPAR database (Journal officiel, open data sets, 2025 update), the rainfall from Open-Meteo weather archives for the Le Pradet grid. Cassini Expertise reproduces these data as they stand, without adjustment.

Drought right now (as at 04/10/2026)

In the commune: recent rain (3 days ago). Rainfall over the last 30 days: 36 mm, against roughly 51 mm expected at this time of year – a 29% deficit.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

This week’s drought watch (as at 05/10/2026)

In the commune: recent rain (4 days ago). Rainfall over the last 30 days: 36 mm, against roughly 52 mm expected at this time of year – a 31% deficit.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

Where do the rains stand today? (as at 12/10/2026)

In the commune: recent rain (4 days ago). Rainfall over the last 30 days: 132 mm, against roughly 61 mm expected at this time of year – a 116% surplus.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

Where do the rains stand today? (as at 19/10/2026)

In the commune: recent rain (1 day ago). Rainfall over the last 30 days: 160 mm, against roughly 70 mm expected at this time of year – a 129% surplus.

A sustained deficit over this window, especially in the growing season, often precedes by a few weeks the drop in the water table shown above: it is the first signal owners can track themselves, before any cracks appear.

When was the aquifer last this low?

The reference piezometric station for the area (002LDFT) has been monitoring the aquifer since 2000 – 26 years of records. As at 02/10/2026, the average level over the last thirty days is 141.35 m NGF (French ordnance datum). Across the whole record, the aquifer has spent only 7.2% of its time below this level: a very low level, rarely reached in the station’s history.

• Last equivalent episode: 04/01/2024 – 2.7 years ago
• Frequency: 26 similar episodes recorded since 2000, i.e. an annual return on average – in hydrologists’ language, a rare event
• Historic minimum: 141.1 m NGF, reached on 01/10/2000

This long memory changes how the risk is read: a low level is not just a weather episode, it is an event whose frequency is known. For a house on clay, it is this frequency that tells you the probability of fresh settlement – and therefore how urgent the precautions are.

Find out more: Article 1641 of the Civil Code and the hidden defects warranty (garantie des vices cachés), explained.

Survey carried out by Frédéric Faucouneau, independent building expert – Antibes, Alpes-Maritimes (06), Var (83), Bouches-du-Rhône (13). Find out more

📅 Last updated 06/11/2026 - Cassini Expertise, independent building expert – departments 06, 83 and 13.