Gas diagnosis

What is a gas diagnosis?


 The gas diagnosis, also known as the "state of internal gas installations", is a compulsory property diagnosis for any sale or rental of property.

This real estate diagnosis makes it possible to identify any defects that render the installation dangerous and that may affect the safety of people and their property.

This diagnosis has an informative value, nevertheless the existence of a Serious and Immediate Danger can lead the diagnostician to ask for the interruption of the power supply of the dwelling.

Gas diagnosis, why should it be measured?


In France, there are many cases of carbon monoxide poisoning, as well as explosions and fires, linked to gas.

All these accidents are caused by non-compliant or poorly maintained installations such as boilers, cooking appliances and other types of gas installations in the home.

Which properties are affected?


 As stated in theArticle L134-6 of the Construction and Housing Code,

In France, landlords must be able to provide tenants and future buyers with a gas diagnosis from 1 July 2017 if :

  • The property was built before 1 January 1975
  • The gas installation is more than 15 years old.

Please note: installations in the outbuildings of individual houses are also covered by this gas diagnosis.

Is gas diagnosis compulsory for all property sales or rentals?


 If the gas installation in the dwelling has been updated and a certificate of conformity (model 2) has been issued then this will replace the diagnosis for a period of 3 years.

1Type of property
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Who should carry out the gas diagnosis?


 The seller must have the diagnosis carried out by a certified professional.

To be valid, the certificate must come from a body approved by the Minister for Energy

  • Sale of a dwelling :
  • By the seller as soon as the property is put up for sale and must be attached to the promise to sell.
  • Renting a dwelling :
  • By all landlords (as of July 2017) and to be attached to the tenancy agreement.

How is the gas diagnosis carried out?


 During this diagnosis, our certified gas diagnostician will examine no less than one hundred and twenty (120) points of the gas installation.

It will carry out concise analyses to verify aspects of the installation according to safety requirements.

This diagnosis is carried out without any dismantling of the installations.

The intervention of our diagnostician only concerns the visible and accessible parts of the gas installation at the time of the diagnosis. 

All the control points of the gas diagnosis relates to the internal gas installation as defined in theArticle 2 of the Order of 2 August 1977 on the technical and safety rules applicable to fuel gas and liquefied hydrocarbon installations located inside residential buildings or their outbuildings.

This diagnosis concerns all installations for the individual production of heat or domestic hot water.

The diagnosis covers several key areas of the internal gas installation, as follows

  • The supply of the installation and appliances such as boilers, bath heaters running on gas (natural, butane, propane), its characteristics, its connection and its tightness.
  • The devices in the installation :
  • gas-fired hobs connected by rigid, flexible or hose pipes if served by a fixed installation
  • boilers: their type, characteristics, connected or not
  • Unplugged water heaters (UWH): their location, characteristics
  • ventilation of premises: their location, the characteristics of the ventilation equipment in the rooms where these appliances operate, air inlets and outlets, etc.
  • ventilation of volumes: minimum surfaces of openings, their location, minimum volumes of rooms where the appliances are located, etc.
  • Combustion, tests (CO measurement, leak detection, flame holding and colouring tests, flow measurement of appliances, etc.)

The diagnosis does not cover :


  • Cooking appliances and mobile heaters supplied by a butane cylinder if there is no fixed installation (pipework attached to a wall).
  • Gas-fired communal heating systems in apartment buildings, as in this case there are no gas-fired appliances in the flat.

The gas diagnosis in no way replaces the control of the conformity of the installation with the regulations in force.

During a gas diagnosis, what are the different types of anomalies that can be found?


In its final report and in accordance with theOrder of 6 April 2007In the event of a problem, our certified diagnostician will have to report the anomalies found during the examination of the various control points:

  • Anomaly A1The installation presents a slight risk that must be taken into account during future work on the gas installation (without delay).

There is no obligation for the owner to carry out any work, the purpose of the gas diagnosis is to make an inventory of fixtures, and any anomalies found cannot be considered as hidden defects by the new buyer.

 The diagnostic technician will report and locate anomalies and also give recommendations and advice.

  • Anomaly A2 : the installation presents a moderate risk that does not require the immediate interruption of the gas supply, but which remains sufficiently important for the diagnostic technician to advise the owner to carry out work on his gas installations as soon as possible. He will also point out and locate the anomalies while giving recommendations and advice.
  • Anomaly Serious and Immediate Danger(DGI): the installation presents a sufficiently serious risk for our diagnostic technician to be obliged to immediately cut off the general gas supply to the installation. This cut-off will be maintained until improvement and compliance work has been carried out.

Our diagnostician will also provide recommendations and advice in his report.

In the case of an A2 or DGI anomaly, the updating work is compulsory for the owner.

How long is it valid?


  •  Rental The gas diagnosis has a validity d6 yearsfrom the date of its completion, so if your tenant leaves the premises after this 6-year period, you will have to carry out a new gas diagnosis before re-letting your property.

On the other hand, if your tenant leaves the premises before the 6 years, you can re-let your property without having to redo a diagnosis

  • Salethe diagnosis has a validityé of 3 yearsfrom the date of its completion.

It is advisable to do this as soon as possible after the property is put up for sale, as this gas diagnosis will be required by the agencies or the future buyer.

Are there any penalties for not having a gas diagnosis?


The The gas diagnosis must be attached to the DDT (technical diagnosis file) which accompanies the compromise or the deed of sale.

  • The absence of the diagnosis is considered as fraud (fraud is a civil offence of defect of consent). Fraud is sanctioned by the nullity of the contract. In addition, the seller or lessor is exposed to penal sanctions.
  • The amount of the rent or the sale price of the property may be reduced.

Non-compliant gas diagnosis at the time of the sale of a property, who should pay for the work to bring it up to standard?


 Bringing the gas installation up to standard

In the event of anomalies or malfunctions noted in the state of the gas system, the law obliges the seller to bring the system into compliance. This work can be carried out either by the seller, who will have the work done at his expense before the sale, or by the buyer, who will have the work done at his expense.

This is an agreement that will be specified on the promise to sell the property concerned.

If the seller does not wish to carry out this work, the potential buyer will be able to request a reduction in the sale price.

Your AOD real estate diagnostician, to secure your real estate transactions

Do you need a property diagnosis for the sale or rental of your property? 

Our real estate diagnosticians are certified, insured and regularly trained and remain at your service!

What are the regulatory texts?


 L134-6 of the Construction and Housing Code

Since 3 January 2003, the adoption of a law concerning this diagnosis has made it possible to establish a reference system for the inspection of an internal natural gas installation and to regulate real estate diagnosis (Article 17 of law n° 2003-8 of 3 January 2003)

From January 2017, it will be progressively integrated into the "Carnet numérique d'entretien et de suivi du logement" (sometimes called "Carnet numérique du logement").

What is the price of a gas diagnosis?


The price varies according to the surface area of the property and is degressive if you have several diagnoses carried out at the same time (such as the DPE diagnosis or the Lead diagnosis for example).

You can get a free quote in less than 24 hours on our website by filling in our form below.

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