To draw water in your garden for watering or sanitary needs... The idea seems attractive. But, the work is complex. For the drilling to last a long time and preserve the groundwater rules are to be observed.
Although the law is very permissive with respect to domestic drilling, you must make a number of declarations according to the characteristics of the installation and ask for authorizations before starting the work. Rules are then to be respected as for the implantation of the drilling on the ground and the methods of its realization. Precautions are essential to ensure the quality of the groundwater.
Mandatory preliminary agreement
- The construction of a well and the drilling of a bore for domestic purposes must be declared to the town hall. According to the Environment Code, domestic use refers to water withdrawals and discharges to cover the needs of homeowners or tenants as well as persons living under their roof and household facilities. Water withdrawals must correspond to the amount needed for food, hygiene care, washing and vegetable or animal productions reserved for family consumption. They must not exceed 1000 m³ per year.
- The declaration must be made on the official Cerfa 13837-01 printout downloadable on the website servicepublic.fr or to withdraw at the town hall. You will describe the characteristics of your installation project. The file must be submitted at least one month before the start of the work.
- Before drilling, the site reseaux-et-canalisation.ineris.fr is imperatively to consult. The company in charge of the building site will be able to locate the other existing networks on your ground or at least to know the coordinates of the operators of the networks concerned. Each of them must be sent a declaration of work or intention to start work or DICT (Cerfa form 14 434 * 02)
- Once the site is completed, the initial declaration made to the town hall must be updated. What has actually been done on the same Cerfa form should be indicated. Qualitative water analysis results should be attached if water is to be consumed.
- To determine the location of the drilling. The work must be at least at:
- - 200 m of landfills and storage facilities for household or industrial waste;
- - 35 m of wastewater treatment systems. If the water drawn feeds the house with drinking water or waters the market gardening requirements are even stricter.
- The tube of the borehole can cross several water tables before reaching the one where the samples are taken. Since they must not pollute each other or enter into communication, the casing of the borehole must be cemented.
- The upper part of the borehole must be "properly closed". Its head must extend at least 0.5 m above the ground and be surrounded by a slab of cleanliness. The soil must be waterproof to a diameter of 2 meters around the borehole and slope outward to prevent water stagnation.
- During the execution of the works, no polluting substance must be poured into the borehole. Thus, access and parking of vehicles near the drill head should be limited and the perimeter closed outside construction hours.
Control to predict
Municipalities or groups of local authorities define in a regulation of water services the respective obligations of the operator of water services, users, owners and subscribers. However, in case of use of water "non-public" a water services officer can check your installation (well, drilling...).
The cost of the control is at your expense. In case of risk of contamination of the water from the public network by water from another source, you may be forced to have work done.
- For the only drilling operation, carried out in a hard rock, it is necessary to count between 100 and 150 € HT the linear meter according to the diameter of the borehole, the casing, the clogging of surface... Add the price of the material (pump for example).
- The volume of water you take through the borehole costs you nothing. It can, however, increase the "collective sanitation charge" of your water bill. Indeed, this fee includes a variable part determined according to the volume of water taken by the user on the public network but also on other sources, since this water is rejected in the collective sanitation system. Thus the water of drawing counts if you use it for sanitary purposes, in the house. However, this is not the case of the one used to water the garden. The volume of the tap water is defined by means of a counter installed and maintained at your expense. Otherwise, it is established in a lump sum manner.
Before you start
- Estimate the amount of water you need. Then check that the groundwater resource you have has the corresponding capacity. Make the same analysis in terms of quality. Water may have characteristics (for example, be rich in iron) making it unsuitable for the intended use. On the underground water resources, you can obtain information from the Bureau of Geological and Mining Research (BRGM) of your department (bgrm.fr) or the Drire.
- Check, in any case, with the town hall and Drire that local regulations are compatible with your project.
- Choose a competent company to carry out your work. Do not hesitate to play the competition. In the light of the specifications, analyze the profitability of the envisaged works. The amount of the bill can sometimes cover many years of water consumption of the public network. On the website of the national union of water wells and boreholes companies (sfe-foragedeau.com) you will find the list of member companies and companies that undertake to respect a quality charter.