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Recover rainwater

Water, a precious natural resource, becomes the stake of a world fight with the aim of preserving it. There is a wide range of products to save this vital good, the apparent tank to be placed on the ground, the buried tank for watering the garden, to wash the car, but also to feed a part of the sanitary installation (washing machine and toilets). A tax credit encourages this type of installation.

Basic tank (520 L)

Basic tank (520 L)

Easy installation at the back of the house, this tank provides extra volume for outdoor cleaning or garden watering

Roman column (550 L)

Roman column (550 L)

This tank provides sufficient water for, once equipped with a mobile pump, provide a pressure jet suitable for watering the garden, washing the car, filling a basin, etc.

Twin 300 L tanks

Twin 300 L tanks

The twinning of several tanks makes it possible to optimize rainwater harvesting and thus ensure the availability of water for longer to water the garden at a very reasonable cost.

Tank Top Tank (1300 L)

Tank Top Tank (1300 L)

The tank Top Tank, easy to install and maintain, is the tank above ground which allows the most important storage in rainwater.

REGULATIONS
Ministerial Decree of 21 August 2008
It specifies the conditions of use of rainwater inside and outside buildings, as well as the conditions of installation, maintenance and monitoring.
The order of October 3, 2008
In relation to the tax credit for rainwater recovery equipment, it sets out the complete list of equipment, materials and appliances eligible for the income tax credit for the main dwelling. The tax credit applies to the amount of equipment and work paid between January 1, 2007 and December 31, 2012 (see official text).
Remediation works are eligible for the zero interest loan.
Decree of 17 December 2008
It covers the control of private drinking water distribution facilities, sampling works, wells and boreholes, and rainwater harvesting works.

The recovery of rainwater can be achieved by means of underground tanks

The recovery of rainwater can be achieved by means of underground tanks

There are two systems of use:

  • a system allowing storage for simple operation (watering the garden, cleaning the vehicles);
  • a second system allowing the recovery of rainwater intended for use both for watering the garden and for domestic use (washing machine and toilet only).

This rigid tank is manufactured in injection molds which gives it exceptional stability. It is perfectly waterproof, thus avoiding all infiltrations that can pollute the rainwater. Its swiveling dome facilitates its connection and its telescopic extension is adjustable in height, which allows an adjustment to the millimeter with the surface of the ground. His pose requires the intervention of a specialist.

Recover rainwater: tank

This rigid tank, through its complementary system to other tanks, allows it to supply water to a part of the house for savings. As long as the level of water contained in the buried tank is sufficient, the pump draws from this tank to feed the watering of the garden, toilets... At the moment when the float indicates a lack of water in the tank, the pump then automatically comes to connect to the urban network. In any case, it can not feed the drinking water network of the house like a sink or a shower, the current regulations prohibits it.

The concrete tank

The concrete tank

There is a range of lightweight concrete tanks, up to 6m3, for the recovery and retention of rainwater. These tanks are manufactured in delayed release. This technique brings a weight gain to the product, a perfect resistance and a great durability.
Good to know
The activated carbon filtration kit eliminates bad odors and makes the water clear. For the washing machine, a UV lamp will be integrated in the filtration to eliminate microbes, bacteria, viruses, algae, mold, etc.

The retention and spreading tank

The retention and spreading tank

Why regulate water?
The development of impervious surfaces in urban areas reduces the natural infiltration of rainwater into the ground and favors the saturation of public drainage networks. This phenomenon is strongly accentuated by climate change and the increasing occurrence of high rainfall intensities. The installation of a holding tank constitutes a temporary storage area for rainwater. It also allows regulated discharge and limits network congestion.
Retention of rainwater is recommended when:

  • the storm basins are saturated
  • evacuation networks are overloaded
  • soil infiltration is too slow

The holding tanks retain and regulate the flow of water in the natural environment, which avoids cellar flooding, for example. They retain a volume of water for use in the garden or habitat. They also exist in lightened concrete.

Spreading modules

The spreading module has been specifically designed for the retention and application of rainwater. Its dual mission is to retain rainwater to regulate flows and avoid flooding, but also to infiltrate the soil to reduce the volumes flowing in the networks. Spreading module installations are primarily intended for the public and industrial sectors. Thanks to its extreme resistance, this buried pond solution allows a wide variety of applications: subdivision, industrial zone...

Recover rainwater: garden

Polyester tanks

Polyester tanks

There is a range of monobloc polyester tanks, up to 70 m3, for the recovery and retention of rainwater. These tanks are made of resin reinforced with fiberglass according to the process of the filament winding straight or helical. This process commonly used in the aeronautical and aerospace industries, has largely proven itself.
It brings significant benefits to the product:

  • insensitivity to corrosion
  • exceptional mechanical strength
  • low weight
  • modularity

Recover rainwater: rainwater

The flexible tank

The flexible tank

It allows a quick and easy installation.

It is very sturdy and easy to move when empty.

The tank must be placed on flat, level and level ground, clean and totally free from perforating elements. The ideal is a bed of sand that can be covered with a geotextile felt. In this configuration, it will safely store the rainwater recovered.
During construction, it can be placed in a crawl space.

Its use can be multiple. The flexible tank can serve as a water reserve for fires, storage of industrial liquids, storage of drinking water, storage of agricultural and wine effluents.


The water consumption per person per day today reaches more than 200 L. When we know that the price of m3 water is constantly increasing and can go up to more than 5 € the m3, saving water must be a shared goal. So opt for a gesture that is both good for our planet and for your wallet.

Recover rainwater: recover

Weather Map France

3 calculation parameters:

Local precipitation in L / m² / yr or mm / yr (1 mm = 1 L / m²)

See weather map France.

Rainwater recovery surface

Roof surface - loss coefficient

Your consumption of rainwater

About 75 L / person / day for garden and habitat use.


A tax credit to encourage rainwater recovery
The National Assembly voted a tax credit of 25% of expenses and capped at 8000 € to help individuals install rainwater recovery systems.

(photos / visuals: BigMat, except special mention)

On the same topic

  • DIY tips
    • Rainwater: recovery and use
    • Evacuation of rainwater: build a sump
    • Cement, lime, sand, gravel and light aggregates: the "binders"
  • Questions answers
    • How to reuse an oil tank?
    • How to recover water for the garden and the house?
    • What waterproofness for a cracked slab?
    • By whom to install a rainwater recuperator?
    • What to do when water invades the crawl space?

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