Boreholes and piezometers: new obligations

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🔎 Key takeaways

The regulatory framework for non-domestic boreholes, drilling, wells, and piezometers is being strengthened by two orders dated March 18, 2026.
Operators will have to use a certified “CertiForage” company for certain construction and decommissioning work.
The requirements are specified throughout the entire lifecycle of the structure : administrative procedures, technical rules, maintenance, inspections, incident management, and report submission.

Please note: This article concerns French legislation. The requirements described may not apply in other countries.

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Whenever a hole of a certain depth is made in the ground—for example, to reach a water table for water extraction drilling or for monitoring its quality using piezometers, or to access a geothermal reservoir—risks of soil or groundwater pollution (e.g., pollution from industrial operations, accidental pollution, flooding, etc.) can arise. Consequently, these structures are subject to specific regulations and monitoring.

A brief overview of the latest regulations in force.

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Regulatory Context

Until 2025, drilling services performed during the commencement of operational work or during the decommissioning of a minor geothermal reservoir required the use of certified companies.Meanwhile, the order of September 11, 2003, set out the requirements applicable to boreholes, drilling, well construction, or underground structures falling under heading 1.1.1.0 of the "Water" nomenclature (IOTA).

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Article 83 of Law No. 2023-175 of March 10, 2023, on accelerating renewable energy production (APER) has extended this certification requirement to all borehole or drilling services, well construction, or underground structures not intended for domestic use for the purpose of groundwater exploration, monitoring, or extraction, and restoration work carried out upon the cessation of operation of these structures, enshrined in the Environmental Code by a decree in September 2025.

Two decrees published on March 18, 2026, have clarified this new regulatory framework, and incidentally repeal the decree of September 11, 2003 as of December 31, 2027, whose initial provisions they adopt and supplement.

One concerns the works themselves, as well as the operating and end-of-life rules for these structures, while the other addresses company certification conditions.

Which structures are now affected?

✔ Purpose of boreholes covered	✖ Purpose of boreholes excluded
Groundwater level lowering Reconnaissance work carried out as part of water prospecting Temporary or permanent groundwater withdrawals, particularly those required for the operation of classified installations (ICPE) and basic nuclear installations (INB) Remediation of contaminated sites and soils by pumping and treating groundwater Measurement, even temporary, of the piezometric level or water table quality parameters (piezometers, etc.), or in-situ hydraulic testing of the water table, particularly as part of geotechnical or environmental investigations and ICPE monitoring Diagnosis and monitoring of groundwater at contaminated or potentially contaminated sites and soils	Geotechnical or environmental investigations, or diagnosis and monitoring of contaminated sites and soils, other than boreholes or soundings intended to measure the piezometric level or water table quality parameters or to carry out in-situ hydraulic tests on the water table. (For example, boreholes intended solely for sampling soil or rock, or for soil gas sampling) Exploration or exploitation of geothermal deposits, or mineral exploration or mining Underground storage of gas, hydrocarbons, and chemical products, which are subject to other regulations Remediation of contaminated sites and soils, except for remediation works involving pumping and treatment of groundwater

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Purpose of boreholes covered

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Purpose of boreholes excluded

Groundwater level lowering
Reconnaissance work carried out as part of water prospecting
Temporary or permanent groundwater withdrawals, particularly those required for the operation of classified installations (ICPE) and basic nuclear installations (INB)
Remediation of contaminated sites and soils by pumping and treating groundwater
Measurement, even temporary, of the piezometric level or water table quality parameters (piezometers, etc.), or in-situ hydraulic testing of the water table, particularly as part of geotechnical or environmental investigations and ICPE monitoring
Diagnosis and monitoring of groundwater at contaminated or potentially contaminated sites and soils

Geotechnical or environmental investigations, or diagnosis and monitoring of contaminated sites and soils, other than boreholes or soundings intended to measure the piezometric level or water table quality parameters or to carry out in-situ hydraulic tests on the water table.

(For example, boreholes intended solely for sampling soil or rock, or for soil gas sampling)
Exploration or exploitation of geothermal deposits, or mineral exploration or mining
Underground storage of gas, hydrocarbons, and chemical products, which are subject to other regulations
Remediation of contaminated sites and soils, except for remediation works involving pumping and treatment of groundwater

What are your obligations as a structure operator?

If you have planned surveying, drilling, well creation, or underground structure works not intended for domestic use, you must:

*as of December 31, 2027* Use a drilling company holding the appropriate "CertiForage" certification.
There are 3 types, from the most comprehensive to the most specific: "All water drilling", "Polluted sites and soils", and "piezometers". Note that the certification named "aquifer module" held by shallow geothermal companies, referred to as "of minor importance," serves as certification under the "All water drilling" module.
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Carry out or have carried out administrative procedures for the creation and operation of the structure under the Installations, Structures, Works and Activities (IOTA) regulations and the anti-damage regulations (work declaration – DT), or during modifications/changes in the use of the borehole (examples: submitting a water law declaration file to the water authority or the prefect for ICPEs, registering the abstraction/monitoring structure with the BRGM Subsurface Database, which will assign it a national BSS identifier, consulting the Single Window in case of a structure outside property boundaries or near external buried networks on the site...).
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Report to the prefect and the mayor without delay any incident or accident likely to affect the quality of groundwater and soil, as well as any evidence of groundwater and soil pollution during the construction of the structure.
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Ensure that the drilling company complies with general rules regarding siting (including compliance with setback distances) and the requirements set in terms of drilling and equipment techniques, as well as controls (site management, choice of materials and equipment, cementing, development and securing of the borehole head, test pumping for abstraction boreholes). *New rules are introduced by the decrees of March 18, 2026, and apply from December 31, 2027; compliance with the provisions of standards NF X10-999 or NF X31-614 is presumed to satisfy these rules*
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Require the drilling company to submit the final work report containing all regulatory information / documents.
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Submit this report to the prefect within 2 months at the latest following the completion of the works (3 months from December 31, 2027), and upload a copy to the dedicated digital application (not yet available).

During the operation of your existing boreholes, wells, or underground structures not intended for domestic use, you must:

Formalize and implement a maintenance program for boreholes and wellhead installations.
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For the specific case of boreholes located within the protection perimeters of water abstraction points for human consumption, and structures that intersect multiple superimposed aquifers, plan for a periodic inspection every 10 years (with submission of the corresponding report to the prefect).
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Inform the prefect of any modification to the technical cross-section of the borehole (depth, casing), potentially associated with a request for modification of the applicable requirements.
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Report to the prefect as soon as possible any incident or accident likely to affect the quality of groundwater and soil, as well as any evidence of groundwater and soil pollution during the operation of the structure.

At the end of a structure's life involving backfilling work, you must:

*from December 31, 2027* Engage a drilling company holding the "CertiForage" certification appropriate.
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Backfill these boreholes using appropriate techniques. *New rules apply from December 31, 2027; compliance with the provisions of standards NF X10-999 or NF X31-614 is presumed to satisfy these rules.*
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Submit to the prefect, within 2 months following backfilling, the final work report including all expected information (except for boreholes drilled for reconnaissance work that are not retained as piezometers or sampling boreholes),
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*from December 31, 2027* Retain the following documents for up to 5 years after the backfilling declaration: Final work report; Subsurface Bank Code (BSS) of the structure; Results of monitoring and maintenance operations performed; Incident tracking documents.

Revision of rules for the creation, operation, and backfilling of soundings, boreholes, and piezometers

Regulatory Context

Which structures are now affected?

What are your obligations as a structure operator?

To learn more: