What is cost of septic tank diagnostic when selling a French second home?

Reader Question: I am looking to sell my second home that has a septic tank installed, but believe I need to have a diagnostic for the tank as part of the sale. Is this expensive?

You are correct that properties with a fosse septique (septic tank) require a diagnostic test before being sold, providing them with a certificate of conformity for the tank if the property is not connected to the mains sewage system. 

This check on the tank must take place no more than three years before the acte de vente (sales deed) of the property is signed, and is mandatory as part of the dossier de diagnostic technique (DDT) series of check certificates you must provide a buyer with.

Your property will only receive a positive certificate if your fosse septique conforms to the correct standards. 

If not, necessary works to bring the system up to regulation will be noted, and these must either be carried out by the seller before the sale, or by the buyer within one year after the acte de vente is signed. 

The buyer can use this document to lower the asking price, if they must carry out the works themselves.

Read more: What is the procedure if septic tank is classed as non-conforme?

The certificate must be provided either by your local Service Public d'Assainissement Non Collectif (Spanc).which covers septic tank regulations, or a private company officially working on behalf of the Spanc. 

A Spanc either covers one commune or a group of communes.

Other private companies offer these diagnostics – which can be useful if checking for issues – but notaires will only officially accept one from the Spanc/a company delegated to carry out a check on their behalf.

The diagnostic will check the tank, among other points, to identify any defects in maintenance or wear, check compliance with technical regulations, that it is not causing any environmental or health risks or public nuisance issues.

Costs

The price of this diagnostic varies between Spanc departments, but is usually between €100 and €150. 

Occasionally, however, it is provided free of charge, funded out of local taxation.

Note that the diagnostic, as part of the DDT, must be provided to the buyer when the pre-sales compromis or promesse de vente is signed.

If the full package of diagnostic certificates, including this one, are not provided there can be sanctions against both seller and the notaire. 

Read more: Do I need to remove a disused septic tank in France after connecting to the mains?