ISO 5667-21:2010

Overview

ISO 5667-21:2010 - Water quality - Sampling - Part 21 provides guidance for sampling drinking water that is distributed by tankers or by means other than contiguous piped distribution systems. The standard covers sampling principles and practical procedures for bulk-supplied potable water during any stage up to the point of consumption or transfer into a piped system. It applies to water supplied by tanker trucks and bulk carriers, and to bulk storage and distribution on aircraft, ships, trains and other vehicles - including situations such as new-system commissioning, re-start after long inactivity, system defects investigations and emergency supply, provided sampler safety is not compromised.

Key Topics

• Scope and applicability - Focus on water already classified as suitable for drinking or potable process use; excludes source-water sampling, piped-contiguous supplies (ISO 5667-5), bottled beverages and vending machines.
• Sampling programme design - Principles for selecting sampling frequency and timing based on purpose, consumer numbers, distributed volume, source variability, treatment and health risk.
• Sampling locations - Guidance to choose representative points (typically at bulk storage inlets and outlets and at delivery/consumption points); when multiple inlets/outlets exist, sites should reflect potential quality differences.
• Pre-collection procedures - Cleaning, disinfection and flushing of tanks and fittings to avoid cross-contamination; hazard assessment when tanks are refilled before emptying.
• Sample collection and handling - Requirements for container materials, sample volumes, preservation and transport to maintain integrity for microbiological and chemical analysis.
• Field measurements & safety - On-site analyses where required, recommended field parameters, and safety precautions for sampling operatives.
• Quality assurance / quality control (QA/QC) - Sampling manuals, training, documentation, sampling records and independent audits to ensure reliable data.
• Biofilm considerations - Guidance on recognizing and sampling biofilms where microbial regrowth or material interactions are suspected.

Applications and Users

Who uses ISO 5667-21:

• Water utilities and bulk water suppliers (tanker operators)
• Maritime, aviation and rail water system managers
• Food and beverage manufacturers using bulk potable water
• Environmental and public health laboratories
• Regulators and inspection bodies planning surveillance, incident response and compliance checks Practical uses include monitoring potable water quality in bulk deliveries, investigating contamination events, validating system commissioning, and establishing safe handling and sampling protocols for transported water.

Related Standards

Referenced and complementary documents for full sampling practice:

• ISO 5667-1 (sampling programme design)
• ISO 5667-3 (preservation and handling)
• ISO 5667-5 (piped distribution sampling)
• ISO 19458 (microbiological sampling)
• ISO 15839 (on-line sensors)
• ISO 5667-14 (QA of sampling)
• ISO/TS 13530 (analytical quality control)

Keywords: ISO 5667-21, water quality sampling, drinking water tanker sampling, bulk water sampling, potable water sampling guidance, tankers, non-contiguous distribution.