Rainwater Draining Toward My House: Slope and Drainage Defects (Var, Alpes-Maritimes)

Direct answer: Article 681 of the French Civil Code governs the flow of rainwater

Have you noticed that rainwater collects against your house or floods your garden while neighbouring plots stay dry? In a housing development (lotissement) or an off-plan purchase (VEFA \u2013 sale in future state of completion), this situation often points to a slope defect, inadequate drainage, or drainage works that do not match the plan you were sold.

Article 681 of the French Civil Code sets out the principle: « Every owner must build roofs so that rainwater flows onto their own land or onto the public road; they may not direct it onto their neighbour’s land. » This rule also applies to works carried out by the developer or promoter: slopes, stormwater networks, gullies and outlets must be designed so that water flows naturally toward the intended low point, without creating a new burden to the detriment of another plot.

If site works have altered the natural drainage pattern, or if the drainage system that was planned was never built, the developer, promoter or contractor’s liability can be engaged. The VEFA guarantees (one-year guarantee of perfect completion, two-year guarantee, ten-year structural guarantee) cover these defects depending on their severity and origin.

The findings needed to establish the defect

Before taking any legal action, the defect must be objectively documented. An independent technical expert report relies on four sets of measurements and observations:

Altimetric survey using a laser level

A rotating laser level is used to measure the actual slopes of your land, driveways, common areas and neighbouring plots. These measurements are compared against the original topographic plan (subdivision plan, site plan from the building permit) and the outdoor landscaping plan provided at the time of sale.

• If the plan specifies a 2% slope toward the outlet and the survey shows a 0.5% counter-slope toward your house, the defect is established.
• If the land was graded differently from what was planned, creating an artificial low point on your property, non-compliance is demonstrated.

Condition of outlets and stormwater networks

The inspection examines the drainage systems:

• Gullies and manholes: are they present, properly sized, and connected to the collective stormwater network?
• Pipes and culverts: correct diameter as per specifications, no obstructions (debris, soil, roots). A smoke or dye test is used to check the continuity of the network and identify blocked or poorly connected sections.
• Ditches and swales: profile, slope, maintenance. A filled-in ditch or a reversed profile sends water back toward the plots instead of collecting it.

Perimeter drainage around the house

If your house has a perimeter drain (buried network around the foundations), the inspection checks:

• Whether it is actually connected to the stormwater network or to a soakaway.
• Whether it is free of clogging (camera inspection, permeability test).
• The continuity of the network (no crushed or blocked sections).

A perimeter drain that is not connected or is blocked worsens water build-up against the walls and can cause basement infiltration, triggering the ten-year structural guarantee if the defect affects the structure’s soundness or makes the property unfit for its intended use.

Flow simulation and identifying the source point

Based on the altimetric survey and local rainfall data, the expert simulates water flow paths and identifies:

• The plot or plots where the water originates.
• Any structures that redirect water onto your plot (low wall, paving, kerb).
• The volume of water involved and the frequency of the events (ordinary rain, storms).

Who is liable? Developer, neighbour, or municipality

Liability depends on the source of the defect and the legal status of the structures involved.

Developer or promoter liability

If the outdoor works (roads, green spaces, networks) do not match the plan sold or accepted building practice:

• Guarantee of perfect completion (1 year): defects apparent at handover or reported within the year (for example, an unconnected gully or a reversed slope noticed during the first rains).
• Two-year guarantee: malfunction of drainage equipment (lift pump, stormwater network).
• Ten-year structural guarantee: if the drainage or evacuation defect compromises the soundness of the structure (structural cracks, subsidence, serious infiltration) or makes the house uninhabitable.

The developer also bears contractual liability if they failed to deliver a building that matches the sales contract (non-compliance with the plan, the subdivision’s specifications, or the co-ownership rules).

Neighbour liability

Article 640 of the French Civil Code states that « Lower-lying land is subject, in favour of higher-lying land, to receiving the water that flows from it naturally without human intervention. » In other words, if water flows naturally from a higher plot to a lower one, the owner of the lower plot must accept it.

However, if the neighbour has altered the natural flow through some structure (embankment, wall, paving that concentrates the water), Article 681 applies: they may not direct water onto your land. Their liability can be engaged if their development worsens your situation.

Municipal liability

If the public stormwater network is undersized, blocked or non-existent, and this shortfall causes backflow or water build-up on your land, the municipality can be held liable. The dispute then falls under the administrative court (liability of the public body for failing to maintain the network).

The expert report: attributing responsibility and costing the fixes

The independent technical expert report (not tied to any insurer or contractor) includes:

• A dimensioned plan of the actual slopes (laser survey) overlaid on the theoretical plan.
• Inspection of the stormwater network (camera, dye/smoke test, pipe diameter measurements).
• Flow analysis: paths, volumes, frequency.
• Technical attribution: design defect, workmanship defect, maintenance failure, or later alteration.
• Corrective recommendations: regrading, creating or unblocking outlets, installing or restoring drains, bringing the stormwater network up to standard.
• Estimated costing of the remedial works.

This report provides the technical basis for invoking the VEFA guarantees, for mediation with the developer, or for legal action before the Grasse Judicial Court (for Antibes and Alpes-Maritimes) or the Toulon Judicial Court (for Var).

Cassini Expertise: laser survey, network testing, independent report (Var, Alpes-Maritimes)

Cassini Expertise operates across the Var (83) and Alpes-Maritimes (06) departments to establish the facts on slope and rainwater drainage defects in housing developments and off-plan purchases. As a former site supervisor and project manager with 15 years in civil engineering, I use Trotec instruments (rotating laser level, hygrometers, thermal camera) and dye/smoke tests to inspect buried networks.

Fully independent: no works carried out, no materials sold. The report is technical, objective, and admissible before the Grasse and Toulon judicial courts.

Phone: 04 22 46 06 04
Email: [email protected]

Frequently asked questions

Who has to prove a slope or drainage defect?

It is up to the property owner affected by the defect to prove that the water is not flowing in line with the plan sold or with accepted building practice. The laser-level altimetric survey and stormwater network inspection provide the objective evidence. The independent technical expertise establishes both the non-compliance and who is responsible.

Can the developer rely on unconditional acceptance of the works?

Unconditional acceptance does not cover hidden defects (defects not apparent during the handover inspection). A slope or drainage defect often only becomes apparent after several rainfall events, sometimes months after handover. The VEFA guarantees (perfect completion, two-year, ten-year) apply regardless of how the handover was accepted.

Can I hold my neighbour liable if the water comes from their property?

Only if the neighbour has worsened the natural flow through some structure (Article 681 of the Civil Code). If water flows naturally from a higher plot to a lower one without human intervention, Article 640 applies: the lower plot must receive the water. The expertise determines whether the flow is natural or artificial.

What is the deadline to take action against the developer for a drainage defect?

The deadline depends on which guarantee applies:
– Perfect completion guarantee: 1 year from handover (defects apparent at handover or reported within the year).
– Two-year guarantee: 2 years from handover (dissociable equipment).
– Ten-year structural guarantee: 10 years from handover (affecting structural soundness or intended use). The period runs from handover, but legal action can be brought up to 10 years after the defect appears if it is a progressive (evolving) defect.

Related articles

• Building expert before purchase in the Var
• Off-plan (VEFA) expertise in Alpes-Maritimes and Var
• G2 soil survey before purchase

📅 Mis à jour le 25/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).