Sainte-Maxime: Clay Soil, Subsidence and Cracks – Official Data

Sainte-Maxime: what drought really does to houses on clay

Can my house in Sainte-Maxime move because of drought? Yes – even though the GASPAR database records no drought decree here, against 16 flood-related decrees since 1982, the officially recognised risk coming rather from runoff off the hills and flooding of the Garonnette. Yet local rainfall tells another story: three dry years out of four (2020, 2022, 2023), then an abrupt catch-up in 2024 with 1,046 mm, i.e. +37% – exactly the kind of shock that puts foundations under strain around the Gulf of Saint-Tropez.

Cassini Expertise, an independent building expert, handles cracks and drought-related damage in Sainte-Maxime and throughout the Var. This page sets out the commune’s official data, exactly as it stands, to help you decide whether your cracks deserve a survey.

Has there ever been a drought decree in Sainte-Maxime?

The GASPAR database (decrees published in the Journal officiel since 1982) records 16 natural disaster declarations (Cat Nat) for the commune:

• 0 drought prefectoral decrees (differential ground movement linked to clay shrink-swell (RGA))
• 16 flood prefectoral decrees and storm

What you should do with this: first check whether your damage appeared during a period covered by a drought decree recognised elsewhere for the area (see GASPAR) and whether you declared the loss to your insurer within 30 days – this is the condition for natural disaster declaration (Cat Nat) compensation. If not, and the house was bought with the cracks already present, the claim against the seller for hidden defect (vice caché) or fraud (dol) remains: keep all documents (dated photos, quotes, letters) before any repair.

Is my plot classified as a clay zone in Sainte-Maxime?

The GéoRisques platform (BRGM) classifies Sainte-Maxime at medium exposure to clay shrink-swell (RGA). This is the benchmark level insurers and notaires consult to assess the risk on a plot: if you are buying, ask the seller or check it yourself on georisques.gouv.fr before signing. Also worth noting: radon potential class 3 across the commune (IRSN/GéoRisques data) – a point to check with a surveyor if you spend time in a basement or a poorly ventilated ground floor.

This classification completes the decree history above: the hazard rating says what can happen, the decrees say what has already happened. A house rated “medium exposure” that has come through one or more dry summers must be examined with all the more care.

Why every file in Sainte-Maxime has to be read through its local context

In Sainte-Maxime, we see a genuine diversity of ground that explains the frequency of the claims we handle: the built fabric steps up from the seafront to the hills of the Débarquement and la Nartassière, by way of the more clayey valleys towards la Croisette or the Plan-de-la-Croix road. The 70s-80s villas, built quickly during the Var tourist boom on lightly reinforced shallow foundations, sit alongside more recent Provençal developments and renovations of old bastides, each responding differently to ground movement. The Sainte-Maxime subsoil has pockets of swelling clay in places, particularly sensitive during prolonged summer drought: the shrinkage of the ground causes differential settlement that weakens wall corners and the junctions between extensions and the original building – very common here given the number of houses enlarged over the decades. The dense Mediterranean vegetation – umbrella pines, cork oaks and olive trees planted close to the homes in the residential estates – aggravates the phenomenon by pumping the residual moisture from the soils in summer, further intensifying the shrink-swell effect. We therefore regularly observe stair-step cracks on gable walls, separation along extensions and slab damage – all classic signatures of the unstable clay soil specific to this part of the Gulf of Saint-Tropez.

Rainfall: the commune’s long memory

The area’s weather archives cover 35 complete years (1991-2025). The driest ever recorded: 2007, with 332 mm over the year, against a local average of 708 mm. 2022 ranks as the 16th driest year out of 35 (622 mm against an average of 708 mm); 2023 follows in 15th place (617 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.

The complete chronology of the 16 natural disasters recognised in Sainte-Maxime

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

• 🔵 08/1983 → 08/1983 – Floods (prefectoral decree of 15/11/1983)
• 🔵 09/1992 – Floods (prefectoral decree of 19/03/1993)
• 🔵 10/1993 → 10/1993 – Floods (prefectoral decree of 08/03/1994)
• 🔵 11/1993 – Floods (prefectoral decree of 08/03/1994)
• 🔵 01/1996 → 01/1996 – Floods (prefectoral decree of 17/07/1996)
• 🔵 09/1996 → 09/1996 – Floods (prefectoral decree of 21/01/1997)
• 🔵 12/2008 – Floods (prefectoral decree of 17/04/2009)
• 🔵 09/2009 – Floods (prefectoral decree of 16/10/2009)
• 🔵 10/2009 – Floods (prefectoral decree of 10/12/2009)
• 🔵 06/2010 – Floods (prefectoral decree of 14/09/2010)
• 🔵 11/2014 → 11/2014 – Floods (prefectoral decree of 03/03/2015)
• 🔵 11/2014 → 11/2014 – Floods (prefectoral decree of 03/12/2014)
• 🔵 10/2018 – Floods (prefectoral decree of 26/11/2018)
• 🔵 11/2019 → 11/2019 – Floods (prefectoral decree of 28/11/2019)
• 🔵 12/2019 → 12/2019 – Floods (prefectoral decree of 12/12/2019)
• 🔵 10/2024 → 10/2024 – Floods (prefectoral decree of 15/12/2024)

Expert reading: 0 droughts and 16 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 Sainte-Maxime

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.

If you notice stains, mould or a crumbling base of wall in Sainte-Maxime, be wary of ready-made answers. Many owners call a resin-injection company straight away or install a mechanical ventilation system without knowing where the problem really comes from. Before any treatment, a diagnosis is needed.

The 4 causes and how to recognise them

• Rising damp: water from the ground rises into the walls by capillary action. The damage generally climbs up to 1 metre, with an irregular front, often accompanied by efflorescent salts.
• Water ingress: water enters from outside (roof, cracked façade, gutter, poorly waterproofed terrace). The stains appear rather high up or localised near an entry point.
• Condensation: linked to a lack of ventilation or a thermal bridge. It mainly affects bathrooms, kitchens, cold wall corners, with no link to the ground.
• Leak: a buried pipe, a defective drain or supply. The damp is often localised, sometimes accompanied by unexplained excess water consumption.

The trap of the diagnosis sold by the treatment contractor

In Sainte-Maxime as elsewhere, many companies selling resin injections or treatment systems offer a “free quote”. The problem: the firm invoicing the treatment has no interest in concluding that your damp comes from a simple pipe leak or a ventilation defect – far cheaper to put right. The diagnosis then becomes a sales pitch, not an independent analysis.

An independent expert has nothing to sell behind the report. He identifies the real cause, even if the solution requires no product or heavy intervention. Before commissioning works in Sainte-Maxime, request an independent diagnosis. To understand the mechanisms and solutions in detail, read the damp guide for 06, 83 and 13.

What the official clay mapping says

The GéoRisques platform (BRGM) classifies Sainte-Maxime at medium exposure to clay shrink-swell (RGA). 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 “medium 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 Sainte-Maxime at medium exposure to clay shrink-swell (RGA). 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 “medium exposure” that has come through one or more dry summers carries a risk of damage that is all the better documented.

Why rainfall matters more than decrees for understanding your cracks

Annual readings on the Sainte-Maxime weather grid (Open-Meteo data):

• 2019: 1,008 mm · 2020: 604 mm · 2021: 696 mm · 2022: 622 mm · 2023: 617 mm · 2024: 1,046 mm
• Average over the period: 765 mm/year, driest year: 2020 (604 mm)
• Three deficit years: 604 mm in 2020, 622 mm in 2022, 617 mm in 2023
• Then a clear catch-up in 2024: 1,046 mm (+37%)

Shrink-swell plays out in two stages: the drought dries out the clay at depth, it shrinks, the first cracks appear; then the rain returns, the ground rehydrates at a stroke and swells again, triggering differential movement. If your villa has shallow foundations – the case for the great majority of those built between 1970 and 2000 – watch your walls 12 to 24 months after a dry summer: that is the usual delay before cracks appear.

Are my cracks worrying? The signs that should prompt action

• 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 simple pencil line or a band of plaster – and check it over several months)
• Associated signs: doors and windows sticking, tiles splitting diagonally, render coming away
• A house built on clay, a tree close by, drainage in poor condition

In Sainte-Maxime, where no drought decree has ever been issued, a build-up of several of these signals justifies calling in an expert before any repair – and before any buying or selling decision. Do not fill an active crack: you lose the proof of how it developed.

Buying or selling a cracked house in Sainte-Maxime: what recourse?

Between the recent decrees and the number of transactions underway, many properties are changing hands with damage kept quiet. If you are the buyer, you have two levers:

• Hidden defect (article 1641 of the Code civil): serious cracks, not visible at the viewing, predating the sale → price reduction or cancellation of the sale, within 2 years of discovery
• Fraud (dol) (article 1137): the seller knew and said nothing → cancellation and damages, within 5 years; the commune’s GASPAR decree then helps underpin the file

To make either stick, the damage first has to be precisely dated: that is the expert’s role, before that of the property-law solicitor (avocat) to whom you then hand the file.

How a drought/clay survey unfolds in Sainte-Maxime

• On-site visit: crack survey and classification, crack-width measurements, functional damage recorded
• Context analysis: clay nature of the ground, the commune’s natural disaster declaration (Cat Nat) history (0 drought decrees), past local droughts
• Costing of works: underpinning, injections, drainage – several possible scenarios, with an order of priority by urgency
• A written report, directly usable by your insurer or your solicitor

Independent expert, with no ties whatsoever to any building contractor. Request a visit in Sainte-Maxime – 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 to Sainte-Maxime (medium 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: Sainte-Maxime combines medium exposure with recurring dry summers, even though no drought decree has been issued. 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, second-opinion expert assessments. Request a consultation.

Frequently asked questions

Is Sainte-Maxime in an at-risk clay zone?

The Var is very broadly affected by the clay shrink-swell (RGA) hazard (BRGM mapping, viewable on georisques.gouv.fr). In Sainte-Maxime, the fact that no drought decree has been recognised in GASPAR takes nothing away from this exposure: the risk is real, not merely theoretical – which is why cracks can appear without any decree covering them.

Can my cracked house in Sainte-Maxime be covered under the natural disaster scheme?

Only if the damage falls within a period covered by a decree (for the latest recognised drought periods, head to GASPAR) and if the declaration was made within 30 days. Failing that, the claim against the seller remains – and there, precisely dating the damage through a survey becomes the central issue in building your file.

Can the figures on this page be checked independently?

Yes: the decrees come from the GASPAR database (Journal officiel, open data, 2025 update), the rainfall from Open-Meteo weather archives for the Sainte-Maxime grid. Cassini Expertise does not adjust these data.

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

In the commune: recent rain (3 days ago). Rainfall over the last 30 days: 26 mm, against roughly 57 mm expected at this time of year – a 54% 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? (as at 05/10/2026)

In the commune: recent rain (4 days ago). Rainfall over the last 30 days: 26 mm, against roughly 59 mm expected at this time of year – a 56% 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 12/10/2026)

In the commune: recent rain (4 days ago). Rainfall over the last 30 days: 142 mm, against roughly 69 mm expected at this time of year – a 106% 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.

This week’s drought watch (as at 19/10/2026)

In the commune: no significant rain for 11 days. Rainfall over the last 30 days: 142 mm, against roughly 80 mm expected at this time of year – a 78% 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.

Aquifer memory: 26 years of measurements, a well-documented context

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.