This Code of Practice W 128 provides a basis for the drilling and dimensioning of horizontal boreholes and the construction of horizontal filter wells. This Code of Practice does not discuss cut‑and‑cover methods ‑ protected by e.g. pit lining ‑ that are sometimes used in the field.

The technical bulletin on hand makes recommendations for these inspections and acceptances of the awarded drilling and well construction work, which have been compiled on the basis of the set of technical rules and which shall be applied on a case‑by‑case basis. It has become apparent that in order to avoid misunderstandings and costly rework, any acceptances and inspections shall have to be agreed beforehand between the parties involved within the scope of the bill of quantities/construction contract, in particular if the specialist company has to make available equipment and facilities at certain dates or work steps. The selection of the acceptances and inspections to be performed in the individual case shall be guided by the hydrogeological conditions and shall be in line with purpose, type and scope of the structure and the materials used.

This Code of Practice W 122 comprises all closing‑off structures for groundwater developments by vertical and horizontal filter wells. The new version incorporates operational issues insofar as they have an immediate effect on the requirements placed on the planning and construction of closing‑off structures.

This Code of Practice W 121 serves as a basis for designing and constructing groundwater monitoring points.The design and construction of groundwater monitoring points is as important for groundwater Monitoring purposes as it is for precautionary, sustainable groundwater protection. Only correctly designed, competently constructed and reliably operating monitoring points can ensure meeting the current requirements of groundwater quality monitoring. A long service life, safe functioning and, in particular, safe sealing,count among some of the important quality features of groundwater monitoring points.This Code of Practice describes how to competently design and construct groundwater monitoring Points for monitoring the quantity and quality of groundwater. It describes the quality requirements for the construction, the building supervision and the acceptance of groundwater monitoring points.

This Code of Practice W 118 serves as basis for the hydraulic and mechanical dimensioning of wells. The references listed represent the minimum requirements on the dimensioning of vertical filter wells.Well dimensioning shall be performed so that a hydraulically effective, functionally reliable and economic water abstraction from the aquifer is guaranteed in the long run. At the same time, apart from the Basic hydrogeological parameters, the operating company's technical specifications and the well construction technology are of importance. A careful selection from the various options in well dimensioning can often minimise problems during later well operation, for instance ageing phenomena.For the planning specialists in drilling and well construction companies, engineering offices and water utilities, the code of practice shall provide assistance for the hydraulic and static dimensioning of vertical filter wells.

This Code of Practice W 115 provides information on the usual drilling methods and their applications. In addition, it contains references to possible faults during water development work, which may have consequences for operation, maintenance (regeneration, rehabilitation) and dismantling. As a summarising abstract it shall serve anyone involved with drilling operations as starting point for project-related considerations.

W 107 Technical Rule ‑ Standard 02/2016

W 400‑1 Technical Rule Standard 02/2015

W 105 Guideline 10/2016

Knowledge of the grain size distribution of water‑conducting granular soil is of great importance for the construction of wells and for the description of the hydrogeological conditions. It is in particular possible to determine the required gravel‑pack diameter in a well's filter section on the basis of the cumulative grain size curve and the grain size distribution curve. In addition, it is possible to derive estimated data for the coefficient of hydraulic conductivity and the porosity of the examined soil sample. Results of the DVGW Research project  Examinations on the stability and clogging of sand and gravel filters during drilling  (DVGW 1982) have been included in the here described procedure to determine the required gravel‑pack diameter. Compared to the Technical Standard W 113  Determination, representation and evaluation of the grain size distribution of water‑conducting granular soils for geohydrological examinations and for the construction of wells  from the year 1983, different practical possibilities for determining the required gravel‑pack diameter and the hydrogeological parameters coefficient of hydraulic conductivity and porosity are demonstrated. Apart from determining the grain size distribution, details on its representation and especially on its evaluation have been provided.

This Code of Practice W 111 shall apply to pumping tests during groundwater prospection and development and to well performance reviews. pumping test or, to be more precise, well or aquifer test is performed between the construction and casing and the commissioning of a well. It documents the net output of the well that was achieved during the development stage, and permits drawing extensive conclusions about the local hydrogeological and hydraulic conditions. This Code of Practice intends to explain how to properly execute pumping tests to acquire and make available the considerable amount of data in the correct form. The information provided by pumping tests is crucially important for the future operation of a well as a repeat pumping test at a later point in time can help identify the well sageing process and record it appropriately, thusfacilitating the timely initiation of regeneration or rehabilitation measures.

DIN 30670 04/2012 english version

This Code of Practice W 402 describes how to collect and process reliable inventory, condition and environmental data about water distribution systems. Condition data notably include data on damages especially failures. These data shall serve mainly as a basis for systematic maintenance in accordance with DVGW W 400‑3 (A) and DVGW W 403 (M). Reliable failure statistics are of particular significance in this context as they serve to predict failure and failure rates and, consequently, determine the residual service lives. This Code of Practice supersedes Instruction Bulletin W 395 dated July 1998.

W 551 Code of Practice 04/2004

W 303 Code of Practice 07/2005

W 270 Technical Standard 11/2007