FAQ - Frequently asked questions

Thanks to its design and the materials used, a flexible tank is self-supporting. It is used solely to store liquids, either temporarily or permanently.

Regulations can vary by region; in most cases, they are departmental regulations called RDDECI. Some circulars include national recommendations on sizing and other guidelines, but departmental regulations are often more detailed. These are drafted by the Service Départemental d’Incendie et de Secours (SDIS). Therefore, it is advisable to contact local authorities when planning a construction, rehabilitation, or extension project (the SDIS of your department).

In general, you should contact your local Chamber of Agriculture to find out the regulations applicable in your department.

CITERNEO fire tanks are equipped to meet the requirements and standards imposed by the DECI. All equipment used complies with regulations and fully meets firefighter connection requirements. Furthermore, CITERNEO QB 09 fire tanks have obtained a favorable technical opinion (Avis Technique Favorable) from the Centre Scientifique et Technique du Bâtiment.

It is perfectly possible to use rainwater collected in a flexible tank for various applications. Rainwater can be used to water gardens, lawns, and plants, as it is naturally soft and chlorine-free, which promotes plant growth. Additionally, rainwater can be used for sanitary installations, particularly to supply toilets, which helps reduce your drinking water consumption and lowers your water bills.

Warning: Rainwater is not potable, so it is strongly discouraged, and in some cases prohibited, to use it for human consumption (drinking, cooking, or washing).

The lifespan of a flexible tank depends on usage conditions and climatic conditions.
The average lifespan of flexible tanks exceeds 20 years.
It is recommended to follow the manufacturer’s instructions for installation, use, and maintenance of your tank. Regularly check the condition of your product to detect any leaks or damage.

Some installations may be eligible for financial subsidies. It is therefore recommended to consult the relevant authorities before starting your work.

The use of a retention system is strongly recommended to recover fertilizer in case of an incident and to prevent contamination of the natural environment.
It is advisable to check the applicable departmental regulations.

To install a flexible rainwater tank, you need a natural, flat, and leveled area with at least a 10 cm layer of sand (type 0.2). The surface must be stable and free of sharp or pointed objects. A geotextile can be placed under the tank for additional protection (in addition to, but not instead of, the sand) if you feel the ground is not clean enough. Proper ground preparation is essential to ensure the durability of your flexible tank.

The space occupied by a flexible tank during delivery depends on its storage capacity. When packaged, these tanks occupy less than 3% of their storage capacity. For example, a 30 m³ tank will be delivered in a package of less than 1 m³, while a 400 m³ tank will be delivered in a package of less than 2.4 m³.

For the installation of your flexible tank, it is essential to follow the instructions in the technical documentation and the installation manual (which can be found in your customer area or in the package).

As a general rule, a building permit is not required. However, it is important to note that specific local regulations may exist and should be checked with your local authority.

You have the option to install your flexible tank in the crawl space of your house; it does not need to be placed before pouring your slab.
The tank is delivered rolled and folded, and can be passed through the access hatch of the crawl space. All our tanks from 1 m³ to 50 m³ fit through an access hatch of 40 cm x 40 cm.

To install a flexible tank, it is essential to follow the instructions in the installation manual. All steps for proper installation are provided, including ground preparation, addition of compacted gravel, and the sand layer. For any questions, it is best to contact us directly.

It is recommended to put a fence around the area where the tank is located to restrict access to authorized personnel only, thereby protecting your tank.

The dimensions specified on your quote or on the website represent the empty dimensions of the product.
It is recommended to leave at least 50 cm on each side of the product (this point is also mentioned in the installation manual). It is also possible to install a weed barrier, which prevents vegetation from growing around the tank and avoids damage during cleaning with equipment such as a lawn mower or string trimmer.

You can install your product yourself, but it is important to carefully follow the instructions in the installation manual.
If you do not feel capable of preparing the platform and installing your flexible tank, you should indeed contact an excavation company or a craftsman such as a plumber.
Hiring a professional offers many advantages, such as installation compliant with standards, increased durability, and improved system efficiency. For complex installations or specific uses of rainwater (such as for human consumption), it is recommended to hire a professional to ensure safety and water quality.

It is recommended to leave at least 20 cm of space above the flexible tank. This promotes air circulation, allows the tank to expand fully when filled with water, and facilitates access to the connections.

A flexible tank cannot be installed vertically due to its soft material composition.

It is strongly discouraged to place a flexible tank in an attic or false ceiling. When the tank is filled, the weight of the water can cause the attic or false ceiling to collapse. Additionally, these structures are not designed to support such loads.

1.Regular inspection
Check the condition of the tank, connections, and accessories for any signs of wear, leaks, or damage.

2.Cleaning gutters and filters
Ensure that the gutters and upstream filters are clean and free of debris to prevent contamination of the stored water.

3.Draining the tank
Partially or fully drain the tank at least once a year to remove sediments and debris that have accumulated at the bottom.

4.Cleaning the interior
Use a soft brush and a garden hose to clean the inside of the tank. Avoid strong chemicals that could damage the material.

It is not necessary to empty your tank or store it during winter. The tank is designed for outdoor installation, regardless of weather conditions (rain, wind, etc.) and temperatures. Its reinforced PVC fabric can easily withstand temperatures from -30° to +70° C. Therefore, winter and cold are not a problem, but there is a risk of freezing during severe frost. In this case, it is recommended not to use or fill the tank.

In fact, it is better to keep it as full as possible, as this maintains some thermal inertia to resist frost. During severe frost, it is recommended to protect the valves from freezing and disconnect above-ground pipes.

The liquid stored in a flexible tank is in contact with all the tank walls. Since the fabrics used are completely opaque, there is no photosynthesis and no algae growth.

Once your flexible tank is installed and in use (filled with water), it is not likely to be damaged by rodents. The rare cases where rodents have damaged a tank involved empty tanks that were rolled up and stored non-airtight in unsecured locations.

All our flexible tanks are produced in France, more precisely in our recently built factory in Amboise (37400 - Indre et Loire).

Flexible tanks are made from a high-quality technical fabric, a very durable polyester coated with PVC.

We select our fabrics based on our experience and the technical characteristics of the liquids that may come into contact with the lining. That is why we offer a wide range of technical fabrics to meet specific requirements and storage conditions. For example, for storing slurry in our flexible tanks, we use a different technical fabric than the one used for storing water.

The QB 09 certification (Qualité Bâtiment) is a mark of quality and durability. It is granted by the CSTB (Centre Scientifique et Technique du Bâtiment), which checks the product and its manufacturing process, as described in a complete technical dossier, to ensure it is suitable for its intended use. It also guarantees that the certificate holder does everything to comply with the technical approval, which is validated at multiple levels by CSTB laboratories, a group of professional experts, as well as CSTB engineers and technicians.

Our flexible tanks can be fully recycled and are reintegrated into specific processing streams for technical fabrics.

When your flexible tank arrives, it is ready to be installed. Everything you need is included: tank, filling, draining, and overflow. Inside the package, you will find a deployment plan and installation instructions.

We have the ability to produce custom tanks. For example, we can manufacture triangular tanks, subject to technical constraints. To make your request, please contact our sales department.

Yes, you can walk on your flexible tank, whether it is empty or full. However, make sure your soles are clean and not pointed to avoid damaging the technical fabric and prevent any risk of leaks or degradation.

To determine the capacity and dimensions of your flexible cistern, several factors need to be considered. Start by estimating the amount of rainwater you can collect, based on the surface area of your roof and the average rainfall in your area. Then identify your water requirements for irrigation, sanitation or other uses. Take into account the space available to install the cistern, whether in a crawl space, cellar or garden. Select a capacity that matches your needs and available space, bearing in mind that cisterns of different sizes can be combined to increase storage capacity if required.

The technical materials we use for our flexible tanks include UV protection treatment. We have reports of tanks installed in desert environments or at high altitudes, exposed to strong UV radiation, that remain functional after several decades of exposure.
Flexible tanks do not require any special maintenance during freezing periods. They withstand temperatures ranging from -30°C to 70°C. Therefore, draining them in winter is not necessary. However, if there is a side valve, it must be protected from frost.

The overflow is a safety opening located at the top of the tank. When the tank is overfilled, the excess water is discharged through the overflow. It is crucial to monitor the filling of your tank to avoid stressing the overflow. Once the tank reaches its full height (also indicated on the recommendation label affixed to the tank), filling must be stopped immediately.

It is not necessary to have pressure to fill your tank. Whether filling by gravity from below, the side, or the top, the water only needs to reach above the tank’s maximum level (communicating vessels principle). However, you can also fill your tank using a pump without any issue. The water will lose its pressure upon entry.

It is essential to filter the water before it enters the tank to prevent clogging and blockage of downstream systems (pump, networks, etc.). Rainwater is filtered using a filter collector or inlet for downspouts or rainwater networks.