Current through Register Vol. 24-18, September 15, 2024
(1) Municipal water suppliers shall determine
distribu-
tion system leakage annually under subsection (2) of this
section or an alternative methodology under subsection (3) of this
section.
(a) Municipal water suppliers
shall include (i), (ii), or (iii) of this subsection in water use efficiency
performance reports developed under WAC
246-290-840 and water use
efficiency programs developed under WAC
246-290-810:
(i) Distribution system leakage totals
calculated under subsection (2) of this section shall be recorded in annual
percent and volume;
(ii)
Distribution system leakage totals calculated under subsection (3) of this
section shall include annual figures and the approved alternative methodology's
numerical stan-dard(s); and
(iii)
For systems not fully metered, the status of meter installation and any actions
taken to minimize leakage.
(b) Municipal water suppliers will be
considered in compliance with this section if any of the following conditions
are satisfied:
(i) Distribution system
leakage calculated in accordance with subsection (2) of this section is ten
percent or less for the last three-year average;
(ii) Distribution system leakage calculated
under subsection (3) of this section meets the numerical standards for the
approved alternative methodology for the last three-year average;
(iii) For systems serving less than five
hundred total connections, distribution system leakage calculated in accordance
with subsection (2) of this section is twenty percent or less for the last
three-year average and the steps outlined in subsection (5) of this section are
completed; or
(iv) A water loss
control action plan has been developed and implemented under subsection (4) of
this section and the system is meeting the implementation schedule.
(2) Calculate the
percent of distribution system leakage annually using the following equation:
DSL = [(TP - AC)/(TP)] x 100
Where:
DSL = Percent of Distribution System Leakage (%)
TP = Total Water Produced and Purchased
AC = Authorized Consumption
(a) Total water produced and purchased, and
authorized consumption must be calculated using data from meters installed
under WAC
246-290-496. Elements of
authorized consumption that cannot be metered, such as fire flow, must be
estimated.
(b) All or portions of
transmission lines may be excluded when determining distribution system
leakage.
(c) Any water that cannot
be accounted for shall be considered distribution system leakage.
(3) Municipal water suppliers may
use an alternative methodology to calculate distribution system leakage if both
(a) and (b) of this subsection are satisfied.
(a) The alternative methodology is contained
in published standards or specifications of the department, Environmental
Protection Agency, American Water Works Association, American Public Works
Association, or American Society of Civil Engineers.
(b) The alternative methodology is approved
for statewide use by the department, to provide a better evaluation of
distribution system leakage than percent of total water produced and purchased,
is appropriate for the system requesting to use it, and uses numerical
standards so that compliance and action levels can be determined.
(4) If the average distribution
system leakage for the last three years does not meet the standard calculated
under subsection (1)(b)(i), (ii), or (iii) of this section, the municipal water
supplier shall develop and implement a water loss control action plan.
Municipal water suppliers shall submit the water loss control action plan to
the department as part of a water use efficiency program under WAC
246-290-810 and upon request by
the department. The control methods described in a water loss control action
plan shall be commensurate with the level of leakage reported. The following
items shall be included in the water loss control action plan:
(a) The control methods necessary to achieve
compliance with the distribution system leakage standard;
(b) An implementation schedule;
(c) A budget that demonstrates how the
control methods will be funded;
(d)
Any technical or economic concerns which may affect the system's ability to
implement a program or comply with the standard including past efforts and
investments to minimize leakage;
(e) If the average distribution system
leakage calculated under subsection (2) of this section is greater than ten and
less than twenty percent of total water produced and purchased, the water loss
control action plan must assess data accuracy and data collection;
(f) If the average distribution system
leakage calculated under subsection (2) of this section is between twenty and
twenty-nine percent of total water produced and purchased, the water loss
control action plan must include elements listed under (e) of this subsection
and implementation of field activities such as actively repairing leaks or
maintaining meters within twelve months of determining standard
exceedance;
(g) If the average
distribution system leakage calculated under subsection (2) of this section is
at thirty percent or above the total water produced and purchased, the water
loss control action plan must include elements listed under (e) and (f) of this
subsection and include implementation of additional control methods to reduce
leakage within six months of determining standard exceedance; and
(h) If the average distribution system
leakage calculated under subsection (3) of this section is over the approved
alternative methodology's numerical standard, the department will take
appropriate compliance actions and work collabora-tively with the municipal
water supplier to ensure the control methods and level of activity are
commensurate with the level of leakage.
(5) Systems serving less than five hundred
total connections may submit a request to the department for approval of an
average distribution system leakage up to twenty percent. The following
information must be submitted to the department with the request:
(a) Production volume;
(b) Distribution system leakage
volume;
(c) Evidence documenting
that:
(i) A leak detection survey using best
available technologies has been completed on the system within the past six
years for purveyors required to develop a small water system management program
under WAC
246-290-105 or within the
approval period of the most recent water system plan for purveyors required to
submit a water system plan under WAC
246-290-100;
(ii) All leaks found have been
repaired;
(iii) The system is
unable to locate additional leaks; and
(iv) Ongoing efforts to minimize leakage are
included as part of the system's water use efficiency program; and
(d) Any technical concerns or
economic concerns, or other system characteristics justifying the higher
distribution system leakage.
Reviser's note: The brackets and enclosed
material in the text of the above section occurred in the copy filed by the
agency and appear in the Register pursuant to the requirements of
RCW
34.08.040.
Statutory Authority:
RCW
70.119A.180 and
43.20.050. 08-03-061, §
246-290-820, filed 1/14/08, effective 2/14/08. Statutory Authority:
RCW
70.119A.180. 07-02-025B, § 246-290-820,
filed 12/22/06, effective 1/22/07.
Reviser's note: The brackets and enclosed
material in the text of the above section occurred in the copy filed by the
agency.
