national multiple family submetering and allocation billing program ...

CHAPTER 8 ISSUES R EGARDING POINT-OF-USE METER
STANDARDS
The recent introduction of point-of-use (POU) meters in the multi-family sector for
measuring consumption for use in billing has created a need to address plumbing code standards
for point-of-use applications. POU meters are used in multi-family dwellings where water use
cannot be measured by other means due to the design of the plumbing systems. POU meters are
considered submeters since they are installed downstream of the utility master meter. They are
designed for installation on the separate water lines going to the various end uses, such as
showers, sinks, toilets, etc. It has been estimated that POU meters are applicable for use in nearly
50% of all multi-family properties, with the average dwelling unit requiring around seven POU
meters. In these dwelling units, larger meters that capture all consumption at one point cannot be
used, because water comes into the dwelling unit from many shared supply lines. It is important
to note that there are already accuracy standards for water meters. However, the current
standards are applied to meters that are tested in the horizontal position with straight piping and,
in the case of the AWWA standard, for cold-water applications. POU meters are being installed
under other conditions such as in the vertical position with bent piping and for hot water
applications. The question that has been raised in deference to consumer protection is, how
accurate are these POU meters under those conditions since the current plumbing codes do not
require testing under these application conditions. Thus, installation standards need to be
developed where none currently apply and, if necessary, incorporated into the appropriate
plumbing and utility codes.
An ad hoc committee was formed to address POU meter application issues by reviewing
the current meter standards, discussing the issues, and developing conclusions and
recommendations for consensus based application standards. The committee’s comments and
conclusions follow the background information presented below on the organizational structure
of metering standards in the U. S and their applicability. Recommendations are presented in
Chapter 9 and in the Executive Summary.
241