Standards and Guidelines
Standards and guidelines for drinking water have evolved over the past
50 years and are continuing to evolve as knowledge increases. Standards
are important in providing a basis for judging the safety of water
supplies but they are also important in ensuring the acceptability of
drinking water, providing a benchmark for water treatment and in some
cases a means of reassuring consumers.
Revised March 2012
There are many influences on standards and not all standards are based
on health so care must be taken in interpreting any exceedence of a
standard. The most important standards relate to the prevention of
waterborne disease caused by pathogens that reach water sources in
faecal matter from humans and animals.
Many chemical contaminants can be found in water from natural sources
and as a consequence of human activities. Standards for these are
mostly based on health, although some are political. WHO in their
Guidelines for Drinking Water Quality provide information on a wide
range of potential chemical contaminants but it would not be
appropriate to simply incorporate all of these into national standards,
which should take into account local issues. Standards for chemicals
usually incorporate a significant margin of safety and an exceedence of
a standard does not necessarily mean that the water is unsafe. Some of
these standards also relate to the acceptability of drinking water,
particularly in terms of taste, odour or discolouration.
New approaches to assuring drinking water safety and quality are being
introduced, particularly Water Safety Plans, which provide a holistic
management tool to prevent problems arising.
This Guide explains and explores how standards are derived, taking
account of the above considerations.
Copies of this Guide are available from the Foundation, price
£15.00, less 20% for FWR Members.
View the full guide