What are the French rules on using rainwater collectors?

Reader question: I have seen a lot online about rainwater collectors and I am thinking about buying one. Are there any rules of which to be aware?

In the past, we have written about how it is perfectly legal to collect and use rainwater that falls on your land or property, even in the case of water restrictions.

You can buy rainwater collectors from most DIY stores in France and some departments even offer financial help with their cost.

However there are strict rules on what you can use rainwater for, how it is collected and how it can be used in your house.

What can I use collected rainwater for?

Rainwater you collect using overground collectors or in-ground silos can be used to water gardens and vegetable patches, wash cars and pathways etc.

It can also be used to wash clothes provided you use it alongside a water treatment device.

It can never be used as drinking water or in food preparation due to the potential presence of harmful bacteria and chemicals.

If you want to connect your rainwater collectors to your home (via taps) you will need to install a completely separate plumbing system.

Inside homes (there is an exception for cellars, annexes etc) rainwater taps and drinking water taps cannot be installed in the same room and must be recognisably different via separate colours and signs, and should have a locking mechanism.

Additionally a plumber will need to install a non-return valve for your rainwater pipes, to avoid polluting drinkable water from the water mains.

To install a rainwater plumbing system you will need to send a déclaration d'usage des eaux pluviales to your local mairie. You can find out what this entails on the service public site here.

Read more: New website tells you the water restrictions in your part of France

How can you collect rainwater?

Rainwater can be collected either using above-ground rainwater collectors or in-ground silos.

Rainwater collectors can be installed on roofs as long as they do not contain asbestos or lead.

Most rainwater collecting devices can be bought at DIY shops and you do not need to declare you are collecting rainwater (unless you are pumping it inside your home, as detailed above).

One point to note is that rainwater can only be collected where it falls.

Article 640 of France’s Civil Code states that landowners should not install systems preventing water running off their property to a neighbouring one.

Dykes cannot be built to prevent rainwater running into another property or to stop it running into yours, nor can you pipe your rainwater to a location which is not part of your property.

The Civil Code also states that if rain has fallen onto a property and remains there it is the legal obligation of that person to deal with it, in the case of stagnating water or health hazards.

What are the penalties for misusing rainwater?

It is essential not to mix collected rainwater with the ordinary public supply. If rainwater collected on your property ends up in the public water system you could face stiff penalties, due to the possibility of polluting the drinking water in your area.

Should a dyke be built to artificially change the flow of rainwater between two properties, one of the involved parties could appeal to the mairie.

The mairie in turn could oblige the other property owner to remove any works impacting the rainfall.

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