BS ISO 5667-21:2010
Water quality. Sampling. Guidance on sampling of drinking water distributed by tankers or means other than distribution pipes
This part of BS ISO 5667 establishes principles to be applied to the techniques of sampling water provided for drinking and for use in the manufacture of food and beverage products.
The guidance given is generally confined to those circumstances where water is drawn from municipal or similar public or private abstraction, treatment or distribution systems for which prior treatment or quality assessment has resulted in the water being classified as suitable for drinking or potable process purposes.
Specifically, this standard is applicable to water that is supplied by tanker or other non-contiguous bulk means, but not contiguously as part of a piped distribution system, during any stage of use up to and including the point of consumption or transfer to a piped distribution system.
BS ISO 5667-21 is also applicable to the distribution and bulk storage of water on aircraft, trucks, trains, ships, and other vessels and vehicles, as well as to sampling situations that can arise during the investigation of system defects, initiation of new systems, re-initiation of systems that have been unused for long periods or emergency situations where the safety of sampling operatives is not compromised.
This standard is one of the specific water-type sampling parts of BS ISO 5667, and deals with the sampling of drinking water, with or without prior treatment, when the water is supplied by means other than a piped distribution system contiguous to a water source.
This part of ISO 5667 should be read in conjunction with ISO 5667-1, ISO 5667-3 and ISO 5667-5.
Effective monitoring of drinking water requires collaboration between sampling programme designers, water operators including transporters and water couriers, sample collectors, laboratory analysts, and data users. This part of BS ISO 5667 gives guidance on the selection of sampling locations and the collection of samples when monitoring drinking water.
Understanding the purposes for monitoring drinking water and the principles behind the methods of analysis is important, since specific sampling protocols can vary widely in accordance with different purposes and different analytical methods.
Examples of sampling purposes include:
- Searching for the cause of pollution within the distribution chain
- Monitoring the quality of drinking water in storage and at the point of use on ships, aircraft and other vessels and vehicles that provide water for drinking, washing, cooking or other purposes
- Assessing the effects of materials in contact with the water on its quality
- Assessing the integrity of a non-contiguous distribution chain.
An important factor to take into account is that the potential for microbial regrowth due to faecal contamination of drinking water is always present and constitutes a genuine risk to human health.
Chemical contamination events also occur, but these are likely to pose chronic hazards rather than the acute effects generated by faecal contamination.