National foreword

This British Standard is the UK implementation of EN 18049‑1:2026.

The UK participation in its preparation was entrusted to Technical Committee CPI/113, Hydrometry.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2026.

This European Standard was approved by CEN on 2 February 2026.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and United Kingdom.

European foreword

This document (EN 18049‑1:2026) has been prepared by Technical Committee CEN/TC 451 “Water wells and borehole heat exchangers”, the secretariat of which is held by AFNOR.

This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2027, and conflicting national standards shall be withdrawn at the latest by October 2029.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

Within its program of work, Technical Committee CEN/TC 451 requested CEN/TC 451/WG 1 “water wells” to prepare the following standard:

EN 18049‑1, Water wells — Part 1: Design.

The EN 18049 series under the main title water wells will consist of the following parts:

Part 1: Design;
Part 2: Construction;
Part 3: Operation and abandoning.

Any feedback and questions on this document should be directed to the users’ national standards body. A complete listing of these bodies can be found on the CEN website.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United Kingdom.

1 Scope

This document is applicable to all types of water wells, whether for public or private use, abstracting from or injecting water to the groundwater, in a variety of applications. These include potable water abstraction, industrial use, irrigation, dewatering, aquifer recharge, and geothermal applications, or for groundwater observation (see Clause 13).

This document does not apply to horizontal wells, groundwater quality monitoring wells in potentially contaminated sites, and closed loop geothermal systems.

This document defines design requirements of water wells for public and private users in accordance with groundwater protection goals. It gives guidelines for all planning steps from preliminary to final executive project design.

A sequential method for designing and dimensioning a well is specified. Based on the hydrogeological conditions and the objectives of the well, a step-by-step process for dimensioning the well is defined. This methodology includes dimensioning for the drilling, filter packs, sealings and screens. Furthermore, selection of appropriate materials, the pump and all other additional well equipment is outlined. With regard to the planning process references are provided for drilling methods, geophysical well logging, well development and pumping tests.

2 Normative references

3 Terms and definitions

4 Project objectives

4.1 Background

4.2 Requirement

4.3 Compliance

5 Site conditions

5.1 Background

5.2 Requirements

5.3 Compliance

6 Geological and hydrogeological characterization

6.1 Background

6.2 Requirements

6.3 Compliance

7 Qualitative risk assessment

7.1 Background

7.2 Requirements

7.3 Compliance

8 Estimation of yield

8.1 Background

8.2 Requirement 1

8.3 Compliance

8.4 Requirement 2

8.5 Compliance

9 Pump selection

9.1 Background

9.2 Requirement

9.3 Compliance

10 Dimensioning of the well

10.1 General background

10.2 Casing

10.3 Annular space

10.4 Formation stabilizer

10.5 Filter pack (gravel pack)

10.6 Annular seal

10.7 Clay plug and separation filter

10.8 Open area coefficient

10.9 Critical entrance velocity

10.10 Length of screen section

10.11 Sump

11 Selection of materials

11.1 General

11.2 General requirements

11.3 Filter pack

11.4 Casing and screen

11.5 Sealing

11.6 Backfilling material

12 Additional well equipment

12.1 Background

12.2 Requirement 1

12.3 Compliance

13 Observation wells

13.1 Background

13.2 Requirement 1

13.3 Compliance

13.4 Requirement 2

13.5 Compliance

13.6 Requirement 3

13.7 Compliance

14 Drilling methods

14.1 Background

14.2 Requirement

14.3 Compliance

14.4 Compliance

15 Drilling fluids

15.1 Background

15.2 Requirements

15.3 Compliance

16 Geophysical well logging

16.1 Background

16.2 Well logging methods

16.3 Quality assurance for the performance of well logging measurements

16.4 Design of logging programmes

17 Well Development

17.1 Background

17.2 Requirement 1

17.3 Requirement 2

17.4 Compliance

17.5 Requirement 3

17.6 Compliance

17.7 Requirement 4

17.8 Compliance

17.9 Equipment

17.10 Specific requirements

18 Pumping test

18.1 Background

18.2 Minimum equipment for the well to be tested

18.3 Location of observations

18.4 Pumping system

18.5 Monitoring equipment

18.6 Performing a pumping test

18.7 Water sampling and analyses

19 Site waste management

19.1 Background

19.2 Requirement 1

19.3 Compliance

19.4 Requirement 2

19.5 Compliance

19.6 Requirement 3

19.7 Compliance

20 Control, maintenance and monitoring

20.1 Background

20.2 Requirement 1

20.3 Compliance

20.4 Requirement 2

20.5 Compliance

21 Evaluation of the design

21.1 Background

21.2 Requirement

21.3 Compliance

22 Project design documents

22.1 Background

22.2 Requirement 1

22.3 Compliance

22.4 Requirement 2

22.5 Compliance

22.6 Requirement 3

22.7 Compliance

Bibliography