Rainwater Harvesting at Home Still Allowed, but Washing Machine Use Now Requires Prefect Approval

Since September 1, 2024, a new decree governs domestic rainwater use in France. Watering gardens, cleaning surfaces or supplying toilets remains possible, while laundry washing is subject to stricter conditions. In the face of recurrent droughts, these rules are primarily designed to safeguard the drinking water network.

The July 12, 2024 Decree replaced the 2008 text and places rainwater among non-potable waters

The current framework rests on Decree no. 2024-796 and on a July 12, 2024 order, in effect since September 1, 2024. This latter provision repeals the August 21, 2008 order. The August 29, 2023 decree, frequently cited, targets non-domestic uses.

According to the official service-public.gouv.fr sheet, water collected from a roof can contain pesticides, metals or asbestos fibers. It is therefore classified as water unfit for human consumption. Only water captured downstream of surfaces that are inaccessible is allowed, provided that the surface is not asbestos- or lead-based.

Watering, soil cleaning, toilet flushing and laundry are permitted, whereas drinking, cooking or washing with this water remains excluded

Outside, the official list includes garden irrigation, cleaning of surfaces, washing the car and decorative fountains. Inside the dwelling, three uses are permitted: flushing toilets, washing floors and washing laundry. By contrast, drinking, cooking, dishwashing and personal hygiene remain prohibited.

However, the washing machine is an exception. According to Annex I of the order, this use requires a declaration to the prefect under Article R. 1322-100 of the Public Health Code. The water must also meet the so-called A+ quality, with no detectable Escherichia coli, hence treatment and an analysis at commissioning.

A completely separate circuit, a visible air gap and a town hall declaration regulate any connected installation

The text sets a strict principle: the rainwater circuit must remain entirely separate from the drinking-water network. If the public network serves only as a supplementary source to fill the tank, a total overflow disconnection, with a visible and permanent air gap, becomes mandatory. Thus, no backflow can contaminate the communal network.

Next, a filter with a mesh no larger than 1 millimeter must precede storage, and an overflow from the tank into the sewers must be fitted with a non-return valve. Moreover, the tapping points are typically marked with “non-potable water” and equipped with a lock. The decree, however, exempts single-family houses from these markings, which the government sheet nonetheless presents as the rule.

Furthermore, as soon as a home uses this water indoors, a declaration to the town hall is required, under the General Code of Local Authorities. It specifies the address and the estimated volume, useful for calculating the wastewater charge.

Regular maintenance, a sanitary register and possible inspections, responsibility rests entirely with the owner

The owner keeps a sanitary log documenting declarations, the layout of the system and interventions. Maintenance includes a visual inspection, replacement of filters, operation of valves and the emptying and cleaning of the tank. Above all, the use of any antifreeze product is prohibited in the system.

A water service officer can inspect a connected installation, at the owner’s expense, in case of risk to the public network. If there is refusal to correct an anomaly, the municipality can shut off the water connection. Finally, contaminating the public network carries penalties of up to 3 years of prison and a €45,000 fine, according to the administration.