How often must I empty my septic tank in France?

Reader question: I installed a septic tank in my house in 2021, but I am not sure how or when I should empty it. Are there any laws about this?

In general, septic tanks (fosses septiques) need to be emptied when they are around half full.

How long it takes for a tank to reach this level depends on the type of tank installed, how often it is used, and how many people use it.

Generally, however, tanks should be emptied roughly every four years, although smaller ones may need to be emptied every two years.

Article L1331-1-1 of the Public Health Code states that it is the responsibility of the property’s resident (homeowner or the person renting it) to maintain the septic tank. This includes emptying it on a regular basis.

There is no law however stating that a septic tank has to be emptied within a certain amount of time.

The Service Public d’Assainissement Non Collectif (SPANC) conducts check ups of septic tanks in France, to ensure they are being kept in good condition.

These tests occur once every four to ten years, and will check if your tank is being emptied regularly enough.

If it is not it could represent an environmental risk to the area surrounding your house.

Tanks can only be emptied by professionals with the correct certification.

How do I know when my tank is ready to be emptied?

Indications that your tank may be reaching saturation are bad smells, sewage or drainage issues, and a random patch of bright green grass in one area of your garden which could indicate a leak or overspill from the tank, with the nutrient-rich sludge feeding the grass.

You can use a pole or stick to measure how full the tank is – you should check when you start to feel resistance (caused by the sludge) and see if that is less than halfway down the tank’s cylinder.

Alternatively, leaks even when the tank is not full, could be caused by a blockage.

If a problem is identified or the tank is over halfway full, you will need to call someone to empty the tank.

Who can empty a septic tank?

Septic tanks must only be emptied by professionals who are accredited by the SPANC, who will come to empty the tank, using special equipment to do so.

The cost of cleaning a tank can be between €150 to €350; the average cost last year was around €210.

Prices may vary, however, so you may wish to ask for quotes from a number of service providers.

When the tank has been emptied, you will be given a certificate (certificat de vidange) which you can show the SPANC at the next inspection.

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