Put a rainwater collector to water the flowers and the garden for free. Depending on its size and location, it can also irrigate all or part of the garden. And the resulting savings are not insignificant!
In France, the average price of water is 3 € / m³. But in some municipalities, it can reach 7 € / m³. A quick calculation makes it possible to estimate the savings made with a rainwater collection tank, as long as the house has a garden or vegetable garden.
This recovered water can also be used to wash the car, bicycles, garden furniture, the terrace, etc. Here, the investment for an aboveground tank and its system is about 60 €.
Its implementation is simple and requires only a few hours, unlike buried models, larger and more expensive, which usually require the use of a construction machine.
The roof provider of water
The volume of rainwater recovered depends on the roof area concerned and the rainfall rate of the area. Normal rain, falling regularly during the night, quickly filled a tank of 250 liters from a surface of 50 m².
In order to obtain maximum efficiency, it is necessary to connect the tank to the downflow of rain water. There are several capture systems to be connected directly to the descent (usually equipped with a valve and a filter that blocks impurities).
They settle at a height higher than the maximum level of water in the tank. Here, three 90° elbows are connected to a pipe to direct the water to the hole provided on the tank. Unusual situation: the owner has chosen to directly connect the descent to the tank, because the roof is that of a small outbuilding. It is possible to recover even more water through a cascade system.
This is the principle of communicating vessels. Once the first tank full, the water flows into the second tank (taking care to provide a cover to keep the water out of the light) by a PVC tube that connects the two tanks from above. Just provide a slight slope (2 cm / m) to facilitate the flow of water from the first to the second tank.
Volumes adapted to the needs
In this case, our gardener only wanted a small water reserve of 250 liters to fill a few watering cans for flowers and plants around the house.
The tank, its support, and its faucet cost him about thirty euros in a garden center. As for PVC tubes and elbows found in a large DIY area, they cost substantially the same price.
The support allows enough space under the tap to slide a bucket or a watering can to fill it with water and avoid having to connect a hose, unattractive and especially impractical.
Using the spirit level, check that the support receiving the tank is level.
If necessary, fine-tune the setting by adding or removing soil or stones under its base.
After drilling the hole to receive the faucet at the bottom of the tank, clean the plastic burrs created here by the hole saw (slow speed).
Position the valve in the opening and hold it against the wall of the tank.
Inside, screw the plastic nut onto the valve thread.
Block the whole.
On the top of the tank, drill with a hole saw 1 cm larger than the diameter of the connecting pipe.
Three elbows are required to complete the installation.
Provide two 90° elbows and two PVC tubes.
Make a blank mounting to ensure proper sizing of the installation, then dismantle.
Once the incline of 2 cm per meter determined to the tank, prepare a third bend at 90°.
Saw the descent and nest the elbow in it.
A grid here supports the PVC pipe with a wire.
The slope is adjusted by sliding a screwdriver between the two strands and turning until you reach the desired gradient.
Connect the tube to the elbow at the top of the tank.
The assembly is not glued, it is possible to change the course of the water as needed.
• Perfect sealing is not essential in this type of installation. When connecting the pipes to the elbows, it is better not to stick them in order to maintain a flexibility of use. In this way, you will have the opportunity to modify, stop, increase the flow of water at your convenience.
• For aesthetic reasons, install the bowl on the side of the house or on the right side of a lower back. It can be hidden by an addiction or vegetation.