To save money on your water bill, you can install a rainwater recovery system but its uses are subject to regulatory obligations.
Each French person consumes 150 litres of drinking water per day, 93% of which is used for personal hygiene, sanitation, laundry, washing up and maintenance of the home. Only 7% is used to drink and prepare meals. The margin of economy, by small daily actions, is important but also by recovering the rainwater. It is quite possible but under conditions because its use is regulated.
No restrictions if you use rainwater outdoors to water your garden or wash the car. It is easy to install a 300 to 2000 litre collector connected to the gutter and equipped with a filter.
On the same principle but for a larger capacity up to 20 m3, the tank can be buried, with a pump, a piping system connected to the water circuit of the house and an electrical control device. This represents important work but allows you to use rainwater for toilets, washing machines and floor washing.
Declare at the town hall the use of rainwater for its interior
Rainwater must only be collected downstream of a non-accessible roof (except for maintenance or repair). No antifreeze should be applied in the storage tank. If your house is connected to the sewerage network, the most common case, you have the obligation to make a declaration of use of rainwater for your home and then to drop it at the town hall of your home. On free paper, you must identify the building concerned, evaluate the volumes of water used in the home (and not outdoors) and indicate where are placed your taps.
At your place, you will need to put a plaque mentioning “non-potable water” with the corresponding pictogram, next to each point of withdrawal of rainwater including toilets. With the exception of the basement, basement and garage, it is forbidden to install a rainwater tap (which must be lockable) in rooms where there is already a drinking water tap.
Finally, regular maintenance must be done every year: filter cleaning, emptying, cleaning and disinfecting the storage tank, checking valves and valves. The follow-up of these interventions must be noted in a health maintenance booklet that will have to be produced in case of technical control of the town hall. If there is a problem, it may force you to close the connection.