How to Collect Rainwater in France: A Practical Guide for Off-Grid Living

Living off-grid in France offers an appealing lifestyle of autonomy and sustainability. Among the key elements of self-sufficiency is water management, and rainwater collection plays a significant role in that.

While collecting rainwater is legal in France, using it—especially inside your home—comes with a detailed set of regulations. This guide will walk you through everything you need to know to collect rainwater in a way that’s both efficient and legally compliant.

Is It Legal to Collect Rainwater in France?

Yes, collecting rainwater in France is perfectly legal—even during water restrictions. Whether you want to reduce your water bill or minimize your environmental impact, setting up a rainwater harvesting system is encouraged. You can buy above-ground or underground collectors in most French DIY stores, and in some departments, you may even qualify for financial assistance.

However, French law strictly regulates how collected rainwater can be used, especially if it’s piped inside your home or comes into contact with the public sewage system. These rules exist primarily to protect public health from contaminants such as pesticides, bacteria, and asbestos from older roofing materials.

What Can You Use Collected Rainwater For?

When used outside the home, rainwater usage is largely unrestricted. It can be used to water gardens and vegetable patches, wash cars, clean patios, and rinse tools. You can also wash floors and flush toilets with it. If treated properly, it can be used for laundry.

However, rainwater cannot be used for drinking, cooking, bathing, or washing dishes. These activities are prohibited under Article R211-127 of the Code de l’Environnement to prevent health risks associated with contaminated rainwater.

To summarize:

Allowed uses:

• Watering plants and gardens
• Washing floors and vehicles
• Flushing toilets
• Laundry (if disinfected)

Prohibited uses:

• Drinking or cooking
• Showering or bathing
• Washing dishes

---

Installing a Rainwater Collection System

Rainwater must be collected directly from where it falls—typically your roof—and cannot be diverted from neighboring properties. According to Article 640 of the French Civil Code, landowners may not obstruct or reroute the natural flow of rainwater. Therefore, installing dykes or piping rainwater to or from another property is not permitted.

You can use either above-ground tanks or underground silos. If you plan to install a rainwater system that connects to your indoor plumbing, you must establish a separate, fully independent water circuit. Taps connected to the rainwater system must not be located in the same room as drinking water taps, unless in special areas like cellars or annexes.

These taps must be:

• Clearly marked with a “Eau non potable” (non-potable water) sign
• Equipped with a locking mechanism
• Fitted with a non-return valve to prevent contamination of the main water supply

---

Legal Obligations for Indoor Use

If your rainwater system is connected to the sewage system, you must file a déclaration d’usage des eaux pluviales with your local mairie (town hall). The declaration should include the property address and an estimate of the volume of rainwater expected to enter the sewage system. This will be used to adjust your taxe d’assainissement collectif (public sewerage tax).

Additionally, French law requires that:

• Taps connected to rainwater must be checked every six months to ensure proper labeling.
• Tanks must be disinfected annually, and filters and taps should be cleaned.
• A maintenance log must be kept. This includes:
  • Details of who inspected the system (if not done by you)
  • A schematic of the rainwater system
  • A service history of the tank(s)
  • Monthly records of rainwater usage

If you rent out your property, the tenant must be informed of how the system works.

Penalties and Compliance Checks

Failure to comply with rainwater regulations can result in serious penalties. If your system is found to pose a contamination risk to the public water supply or sewage system, your local mairie can require you to upgrade or shut it down. If your system causes actual pollution, you may face fines up to €45,000 and even three years in prison.

Local authorities are authorized to inspect rainwater systems and verify that they meet hygiene and safety standards.

Conclusion: A Sustainable Path Forward

Rainwater harvesting in France is a valuable tool for off-grid and eco-conscious living, but it must be done responsibly. With the proper setup, maintenance, and legal compliance, you can significantly reduce your reliance on public water systems without risking penalties.