UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
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Date Signed: September 16, 1987
MEMORANDUM
SUBJECT: Definition of a Non-Transient, Non-Community Water System
FROM: Paul M. Baltay, Director
State Programs Division (WH-550E)
TO: Regional Drinking Water Branch Chiefs
Regions I-X
As you know, the recent VOC regulations officially defined a new category of water
systems — non-transient, non-community water systems (NTNCWS). Section 141.2 of the
National Primary Drinking Water Regulations defines a NTNCWS as a public water system that
is not a community water system and regularly serves at least 25 of the same persons over six
months per year (emphasis added). We have recently been asked to further define "regular" as it
appears in the definition.
In our view, "regular" is more of a qualitative than quantitative term. A sizeable portion
of many individual's daily water consumption occurs away from home. Further, in most
instances, this consumption occurs at the same place, from the same water supply for extended
periods of time. If the water being consumed in such cases is being supplied by a non-community
system rather than a community system, a gap in health protection exists. The NTNCWS
category, as noted in the preamble, was conceived to protect individuals from potential adverse
health effects as a result of longterm consumption of water from a non-residential source. This
protection is to encompass schools, day care centers, nursing homes, institutions such as prisons,
factories and offices which provide water to a fixed population of 25 or more people. In addition,
other service areas such as hotels, resorts, hospitals, and restaurants were intended to be covered
if they employ more than 25 people and are open six or more months of the year. Although we're
reluctant to define regular service or fixed population in terms of hours per day and days per
week, you probably will be, or have been asked for such a quantitative definition. We therefore
recommend using four hours or more per day, for four or more days per week, for 26 or more
weeks per year as a guideline for the term "regular" as it relates to NTNCWSs. Our concern in
offering such a definition is that we will all become mired in numerical games and lose sight of
the fundamental intent of protecting health.
Our goal is for States to have completed a good (not perfect) inventory of NTNCWSs by
October 1, 1988. We believe this goal can be effectively achieved by reviewing service area
characteristics and populations. Systems which are schools, day care centers, nursing homes,
institutions, factories and businesses with populations of 25 or more would be reclassed as
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NTNCWSs. Large hotels, resorts complexes, hospitals, etc., will most likely employ more than
25 people and would be classed as NTNCWSs. Other non-communities can be checked on a
planned schedule (which could extend beyond October 1, 1988 if the State has a large number of
NCWSs). States should, however, be able to begin FY 1989 with a reasonably sound NTNCWS
inventory.
The current version of FRDS (15) will accept the NTNCWS designation beginning
February 1, 1986. FRDS II will process NTNCWS designations as soon as FRDS II is available.
If there are any objections to these guidelines, please let me know. Otherwise I will
assume that you and the States in your Region are in agreement with our philosophy and goals.
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