What is a SPANC report, and what does a non-compliant fosse cost?

French House Check. 16 September 2026.

The SPANC report is the official inspection of a house's private drainage system. If it says non-compliant, the buyer must bring the system into line within one year of completion, and a replacement on a rural site commonly costs EUR 9,000 to EUR 15,000. Ask for the report before you offer.

What the report is

SPANC is the public body that inspects private sewage installations (assainissement non collectif). For any sale of a house not connected to mains drainage, the seller must supply a SPANC report less than three years old. It grades the installation and names the faults.

What non-compliant means for the buyer

Under article L.1331-11-1 of the code de la santé publique, the buyer of a non-compliant installation must carry out the works within a year of the sale. The work has a legal deadline and cannot be deferred.

The size of that cost depends on the grade:

• A missing or non-compliant outlet, an undersized filter bed or an inaccessible inspection hatch: the cheaper end, and the system usually goes on working meanwhile.
• No treatment stage, or a direct discharge to a ditch or stream: a complete new installation, with a soil study and design, at the top of the range or beyond it where the ground drains badly.

Why get it early

It is the seller's obligation, it already has to exist for the sale, and it is a document rather than an opinion. Asking costs nothing, and the report names the faults that set the cost. Adverts that say "fosse non conforme" have disclosed the fact but not the grade. The grade decides whether the work sits nearer EUR 9,000 or EUR 15,000.

On the visit

• Find the tank and the outlet. Ask when it was last emptied.
• Ask directly what the SPANC report says is wrong.
• Look at where a new filter bed could go: the ground, the slope, the distance to any well or watercourse.

A report from us states whether the advert declares the drainage, what the law requires, and the cost band for the type of site. The SPANC report shows where in that band the house falls, and an installer's quote gives the figure.