ISO 5667-11:2009

Overview

ISO 5667-11:2009 - "Water quality - Sampling - Part 11: Guidance on sampling of groundwaters" provides practical guidance for planning and undertaking groundwater sampling to assess water quality, detect contamination, and support resource management, protection and remediation. The standard covers sampling from both the saturated (below water table) and unsaturated (above water table) zones. It is guidance-focused (not a prescriptive protocol) and is not intended for day-to-day operational control of potable abstractions.

Keywords: ISO 5667-11, groundwater sampling, water quality, groundwater monitoring, sampling guidance

Key Topics

The standard addresses the full sampling lifecycle for groundwaters, including:

• Sampling strategy and programme design
  • Defining objectives, selecting sampling points and networks (multiple boreholes, nested piezometers)
  • Parameter selection and sampling frequency considerations
• Types of monitoring installations and methods
  • Unsaturated-zone and saturated-zone monitoring techniques
  • Multi-level samplers, piezometers, packers and well design considerations
• Sampling procedures
  • Purging, trial pits, sampling of free‑phase contaminants (LNAPLs, DNAPLs)
  • Materials selection for sampling equipment and prevention of cross-contamination
• Quality assurance / quality control
  • Sample identification, records, QA/QC measures and reporting
• Health and safety
  • Safety precautions for fieldwork and handling of potentially contaminated groundwater
• Annexes provide tools such as a nomogram for calculating sampling frequency and an example sampling report.

Keywords: piezometer, packer, LNAPL, DNAPL, aquifer, sampling frequency, QA/QC

Applications

ISO 5667-11:2009 is designed for practitioners and organizations involved in groundwater quality work:

• Environmental consultants and hydrogeologists conducting site investigations or contamination assessments
• Remediation project managers and engineers monitoring cleanup performance
• Water utilities and resource managers assessing supply quality and aquifer status
• Regulators and laboratories using sampling data for compliance, risk assessment and model calibration

Practical benefits include improved consistency of groundwater monitoring programmes, reduced sampling contamination risk, and better alignment of field methods with data-quality objectives.

Keywords: groundwater monitoring, contamination assessment, resource management, sampling programme

Related Standards

ISO 5667-11 should be used alongside other parts of the ISO 5667 series, particularly:

• ISO 5667-1 (sampling programme design)
• ISO 5667-3 (preservation and handling)
• ISO 5667-14 (quality assurance of sampling)
• ISO 5667-22 (design and installation of groundwater sample points)

Using ISO 5667-11 with these related standards helps ensure robust, defensible groundwater sampling and water quality data.