Septic tanks and the SPANC: inspection, sale, upgrade

Who is affected, and who inspects

Any building that cannot be connected to the public sewer network must be fitted with an individual system, for example an all-waste septic tank or a micro treatment plant; this is the case in an off-mains drainage zone or for a building exempted from connection (service-public.gouv.fr, fiche F447). The owner must ensure its regular maintenance and periodic emptying by an approved person (CSP, art. L1331-1-1).

Each commune (municipality) or grouping of municipalities has a SPANC. Its inspection duties are compulsory (service-public.gouv.fr):

• examining the design of new systems or systems to be renovated;
• checking that the works have been properly carried out, before backfilling;
• inspecting the operation and maintenance of existing systems, at a frequency set by the commune in its service regulations, 10 years at most.

The inspection is compulsory and charged for; the user cannot choose another provider. The SPANC sends a notice of visit at least 7 working days beforehand, and its officers have a right of access to the property (service-public.gouv.fr).

Maintenance and emptying

Maintenance mainly consists of emptying the tank and the grease trap, by the commune if it offers this service or by a firm approved by the préfet (State representative in the département). The frequency depends on the sludge level, which should generally not exceed 50% of the working volume (service-public.gouv.fr). Keep the emptying receipts: the SPANC checks maintenance.

The redevance d’assainissement non collectif (off-mains drainage charge), often billed with the water, includes an element for the inspection, billed to the owner, and possibly an element for maintenance if this service is used. If unpaid 3 months after a formal notice, it is increased by 25% (service-public.gouv.fr).

Unfavourable inspection outside a sale

The owner carries out the works required by the inspection report within 4 years of being notified of it (CSP, art. L1331-1-1). Service-public.gouv.fr specifies that this period concerns systems posing a danger to health or a proven risk of pollution.

If the inspection is refused or obligations are not met, the commune can claim a sum at least equal to the charge, increased by up to 400% (CSP, art. L1331-8), and, after formal notice, have the essential works carried out automatically at the owner’s expense (art. L1331-6).

If a mains sewer reaches the street, connection becomes compulsory within 2 years of it coming into service (CSP, art. L1331-1).

On a sale: the report under 3 years old

The document drawn up after the SPANC inspection is part of the dossier de diagnostic technique (CCH, art. L271-4, 8°). This pack is provided by the seller and attached to the promesse de vente (preliminary sale contract) or, failing that, to the acte authentique (final deed). The report must be less than 3 years old when the deed is signed; if it is older or does not exist, updating it is the seller’s responsibility (CSP, art. L1331-11-1). The seller makes an appointment with the SPANC, whose contact details are available at the mairie (town hall).

Without this document still valid at signature, the seller cannot exclude the garantie des vices cachés (warranty against hidden defects) for that matter (art. L271-4). The notaire (notary) then sends a certificate of sale to the commune no later than 1 month after signature. The full list of surveys is given in diagnostics obligatoires (mandatory surveys).

After the purchase: one year to bring it up to standard

Article L271-4 of the CCH is clear: “If the off-mains drainage system does not comply when the final deed of sale is signed, the buyer shall have the compliance works carried out within one year of the deed of sale.”

The seller can carry out the works before the sale; otherwise, their cost becomes part of the price negotiation (service-public.gouv.fr). The éco-prêt à taux zéro (zero-rate eco-loan) can, subject to conditions, finance these works.

Discrepancy to note. Fiche F31685 on service-public.gouv.fr (verified on 26 February 2025) states that the seller “must carry out works” in the year following the deed, with the buyer taking them on only if the seller declines, and that the report is handed over “at the time the final deed is signed”. The law in force places the obligation to carry out works on the buyer and requires the report to be attached from the preliminary contract (CCH, art. L271-4); this guide follows the law. Fiche F447 on the same site does refer to it being attached to the preliminary contract.

Which professional to consult

The notaire (notary) checks that the SPANC report is less than 3 years old, attaches it to the preliminary contract and reminds the buyer of their obligation to carry out works within the year. The other surveys in the pack, such as asbestos or electrics, are a matter for a diagnostiqueur (property surveyor). The agent immobilier (estate agent) selling a house with individual drainage can request the report as soon as it goes on the market, to avoid delaying the preliminary contract.