A free resource, rainwater can meet many needs in the home and garden. The point on what you need to know to recover and use this water in the best conditions.
Rainwater: what for?
One person consumes approximately 150 L of water per day. A consumption that amounts to around € 700 per year for a family of four. If rainwater cannot replace all the water used in the house since it cannot be used for washing, cooking, washing dishes and even less being consumed, it can nevertheless cover more than 40% needs. Indeed, it is perfect for flushing water, for laundry, cleaning hard floors or watering the garden.
Rainwater: how to collect it?
A zinc or PVC rainwater collector is installed on a gutter downpipe. The water then falls into a noted tank of a filter in order to prevent the leaves and mosses from falling into the tank. When the tank is full, a manual inverter allows water to flow to the drainage network. This type of collector is well suited for outdoor use only. However, remember to empty the tank before freezing and store the pump in a safe place. For those who wish to make the most of rainwater resources, a larger tank can be buried, which will be supplied by several downspouts. An overflow drains excess water when the tank is full.
Rainwater harvesting: what cost?
A 500 L tank with the material, bought in DIY stores, intended for outdoor use (watering, washing the car, etc.) costs on average € 200. It can be amortized in a big year. For a buried tank of 5 m3, its equipment, the earthworks and the connections, intended to supply washing machine, flushing toilet… it is necessary to count a much larger budget: approximately 5,500 €, tax credit deducted. The amortization will also be much longer: around 18 years for a family of four.
Rainwater tank: what steps?
If after use, rainwater is discharged via an individual sanitation system, no administrative procedure is necessary. But if it is rejected in a collective network, it will be necessary to make a declaration in town hall. In general, as soon as the tank of a buried tank exceeds by more than 60 cm the surface of the ground, a declaration in town hall is necessary. The public drinking water distribution service has the right to carry out an inspection of the installation.
Rainwater harvesting: what aids?
Buried tanks for domestic use (excluding watering, therefore) benefit from a 7% VAT if the accommodation is more than two years old, as well as a 15% tax credit. The installation must be carried out by a professional. The tax credit applies to the price of the tank indicated on the invoice from the company having carried out the work, excluding labor. It concerns the amount including tax of the material. To be valid with the Public Treasury, this invoice must include the details detailed in the decree of November 13, 2007. Certain general, regional, departmental councils and the ANAH also offer assistance.