United States
Environmental Protection
Office of Water
EPA 816-F-97-006
June 1997
EPA is providing advance notice of proposed rulemaking that would revise the
monitoring requirements for sixty-four chemicals in drinking water, and is seeking comment on
draft permanent monitoring relief guidelines and several suggestions for reducing regulatory
burden. These changes would affect chemicals for which EPA has established national safety
standards in drinking water, which may occur in the source water of public water systems, and
which are regulated on the basis of chronic health effects over a 70 year period.
Chemical Monitoring Reform would affect community water systems (CWSs) and non-
transient, non-community water systems (NTNCWSs)
o CWSs are those systems which deliver water to at least 15 service connections used by
year round residents, or regularly serve at least 25 year round residents e.g., cities and
o NTNCWSs are those systems which are not community water systems and which serve at
least 25 of the same people over six months of the year e g, schools, factories or other
facilities with their own water supplies.
Chemical Monitoring Reform would reduce the chance of drinking water contamination
going undetected and, at the same time, reduce unnecessary monitoring and reporting. It would
o Systems that States determine may be at risk of contamination to sample at higher
frequencies, based on each system's vulnerability to contamination; and
o Systems with little or no risk of contamination to sample once every five years.
These changes would: provide more cost effective health protection by focusing public
resources on water systems at risk of contamination and the chemicals posing that risk; and
further increase the chance of detecting contamination by requiring States to schedule all
sampling during the periods of greatest vulnerability, based on local circumstances.

Permanent Monitoring Relief would provide States with an option to grant additional
monitoring flexibility, if the State has an approved Source Water Assessment Program, and has
completed source water assessments for its systems. The additional flexibility that the State
could offer includes:
(1)	Allowing sampling waivers to further reduce sampling frequency, if a State determines
that a system is unlikely to become contaminated, or that the contamination will remain
reliably and consistently below the MCL during the period of the waiver;
(2)	Under certain conditions, allowing systems with multiple wells or withdrawal points that
draw from the same source water to designate the most vulnerable point to sample instead
of sampling at all points;
(3)	Under certain conditions, allowing multiple systems that use the same source water to
designate one or more sampling points that could be used as surrogate sampling point(s)
to satisfy the monitoring requirements for all of the systems; and
(4)	Allowing reduced monitoring for nitrate when historical records of sampling show that
the system has very little or no contamination.