Current through August 31, 2023
01.
Quantity and Pressure Requirements. Design requirements regarding
pressure analysis are found in Section
542.13. (3-24-22)
a. Minimum Capacity. The capacity of a public
drinking water system shall be at least eight hundred (800) gallons per day per
residence. (3-24-22)
i. The minimum capacity
of eight hundred (800) gallons per day shall be the design maximum day demand
rate exclusive of irrigation and fire flow requirements. (3-24-22)
ii. The minimum capacity of eight hundred
(800) gallons per day is only acceptable if the public drinking water system
has equalization storage of finished water in sufficient quantity to compensate
for the difference between a water system's maximum pumping capacity and peak
hour demand. (3-24-22)
iii. The
design capacity of a public drinking water system for material modifications
may be less than eight hundred (800) gallons per day per residence if the water
system owner provides information that demonstrates to the Department's
satisfaction the maximum day demand for the system, exclusive of irrigation and
fire flows, is less than eight hundred (800) gallons per day per residence.
(3-24-22)
b. Pressure.
All public water systems shall meet the following requirements: (3-24-22)
i. Any public water system shall be capable
of providing sufficient water during maximum day demand conditions, including
fire flow where provided, to maintain a minimum pressure of twenty (20) psi
throughout the distribution system, at ground level, as measured at the service
connection or along the property line adjacent to the consumer's premises.
(3-24-22)
ii. Public Notification.
(3-24-22)
(1) During unplanned or emergency
situations, when water pressure within the system is known to have fallen below
twenty (20) psi, the water supplier must notify the Department, provide public
notice to the affected customers within twenty-four (24) hours, and disinfect
or flush the system as appropriate. When sampling and corrective procedures
have been conducted and after determination by the Department that the water is
safe, the water supplier may re-notify the affected customers that the water is
safe for consumption. The water supplier shall notify the affected customers if
the water is not safe for consumption. (3-24-22)
(2) During planned maintenance or repair
situations, when water pressure within the system is expected to fall below
twenty (20) psi, the water supplier must provide public notice to the affected
customers prior to the planned maintenance or repair activity and shall ensure
that the water is safe for consumption. (3-24-22)
iii. If an initial investigation by the water
supplier fails to discover the causes of inadequate or excessive pressure, the
Department may require the water supplier to conduct a local pressure
monitoring study to diagnose and correct pressure problems. Compliance with
these requirements by water systems that do not have a meter vault or other
point of access at the service connection or along the property line adjacent
to the consumer's premises where pressure in the distribution system can be
reliably measured shall be determined by measurements within the consumer's
premises, or at another representative location acceptable to the Department.
(3-24-22)
iv. Copies of pressure
monitoring study reports required under Subsection
552.01.b.iii. detailing
study results and any resulting corrective actions planned or performed by the
public water system shall be submitted to the Department in accordance with
these rules. (3-24-22)
v. The
following public water systems or service areas of public water systems shall
maintain a minimum pressure of forty (40) psi throughout the distribution
system, during peak hour demand conditions, excluding fire flow, measured at
the service connection or along the property line adjacent to the consumer's
premises. (3-24-22)
(1) Any public water
system constructed or substantially modified after July 1, 1985.
(3-24-22)
(2) Any new service
areas. (3-24-22)
(3) Any public
water system that is undergoing material modification where it is feasible to
meet the pressure requirements as part of the material modification.
(3-24-22)
vi. Any public
water system shall keep static pressure within the distribution system below
one hundred (100) psi and should ordinarily keep static pressure below eighty
(80) psi. Pressures above one hundred (100) psi shall be controlled by pressure
reducing valve stations installed in the distribution main. In areas where
failure of installed pressure reducing valve stations would result in extremely
high pressure, pressure relief valves may be required. The Department may
approve the use of pressure reducing devices at individual service connections
on a case by case basis, if it can be demonstrated that higher pressures in
portions of the distribution system are required for efficient system
operation. If system modification will cause pressure to routinely exceed
eighty (80) psi, or if a check valve or an individual pressure reducing device
is added to the service line, the water system owner shall notify affected
customers. Notification may include reasons for the elevated pressure, problems
or damage that elevated pressure can inflict on appliances or plumbing systems,
and suggested procedures or mitigation efforts affected property owners may
initiate to minimize problems or damage. (3-24-22)
vii. The Department may allow the
installation of booster pump systems at individual service connections on a
case by case basis. However, such an installation may only occur with the full
knowledge and agreement of the public water system, including assurance by the
water system that the individual booster pump will cause no adverse effects on
system operation. (3-24-22)
viii.
For elevated storage tanks, pressure calculations during peak hour demand shall
be based on the lowest water level after both operational storage and
equalization storage have been exhausted. Pressure calculations during fire
flow demands shall be based on the lowest water level after operational
storage, equalization storage, and fire suppression storage have been
exhausted. (3-24-22)
ix. For
hydropneumatic tanks, pressure calculations shall be based on the lowest
pressure of the pressure cycle and this requirement shall be noted in the
operation and maintenance manual. (3-24-22)
c. Fire Flows. Any public water system
designed to provide fire flows shall ensure that such flows are compatible with
the water demand of existing and planned fire-fighting equipment and fire
fighting practices in the area served by the system. (3-24-22)
d. Irrigation Flows. (3-24-22)
i. Any public water system constructed after
November 1, 1977, shall be capable of providing water for uncontrolled,
simultaneous foreseeable irrigation demand, which shall include all acreage
that the system is designed to irrigate. (3-24-22)
(1) The Department must concur with
assumptions regarding the acreage to be irrigated. In general, an assumption
that no outside watering will occur is considered unsound and is unlikely to be
approved. (3-24-22)
(2) An
assumption of minimal outside watering, as in recreational subdivisions, may be
acceptable if design flows are adequate for maintenance of "green zones" for
protection against wildland fire. (3-24-22)
ii. The requirement of Subsection
552.01.d.i. may be modified
by the Department if: (3-24-22)
(1) A
separate irrigation system is provided; or (3-24-22)
(2) The supplier of water can regulate the
rate of irrigation through its police powers, and the water system is designed
to accommodate a regulated rate of irrigation flow. The Department may require
the water system to submit a legal opinion addressing the enforceability of
such police powers. (3-24-22)
iii. If a separate non-potable irrigation
system is provided for the consumers, all mains, hydrants and appurtenances
shall be easily identified as non-potable. The Department must concur with a
plan to ensure that each new potable water service is not cross-connected with
the irrigation system. (3-24-22)
02.
Ground Water. (3-24-22)
a. Public water systems constructed after
July 1, 1985, and supplied by ground water, shall treat water within the system
by disinfection if the ground water source is not protected from contamination.
(3-24-22)
b. The Department may, in
its discretion, require disinfection for any existing public water system
supplied by ground water if the system has repeated coliform present samples or
E.coli MCL exceedances, and if the system does not appear adequately protected
from contamination. Adequate protection will be determined based upon at least
the following factors: (3-24-22)
i. Location
of possible sources of contamination; (3-24-22)
ii. Size of the well lot; (3-24-22)
iii. Depth of the source of water;
(3-24-22)
iv. Bacteriological
quality of the aquifer; (3-24-22)
v. Geological characteristics of the area;
and (3-24-22)
vi. Adequacy of
development of the source. (3-24-22)
03.
Operating Criteria. The
operating criteria for systems that provide filtration shall be as follows:
(3-24-22)
a. A project specific operation and
maintenance manual shall be provided as required in Subsection
501.12. See definition of
Operation and Maintenance Manual in Section
003 for the typical contents of an
operation and maintenance manual and the included operations plan. For the
operations plan in the operation and maintenance manual, additional guidance
for several types of filtration systems can be found in the Department's SWTR
Compliance Guidance referenced in Subsection
002.02. (3-24-22)
b. The system shall conduct monitoring
specified by the Department before serving water to the public in order to
protect the health of consumers served by the system. (3-24-22)
c. New treatment facilities shall be operated
in accordance with Subsection
552.03.a., and the system
shall conduct monitoring specified by the Department for a trial period
specified by the Department before serving water to the public in order to
protect the health of consumers served by the system.
(3-24-22)
04.
Chlorination. Systems that regularly add chlorine to their water
are subject to the provisions of Section
320. Systems using surface water or
ground water under the direct influence of surface water, are subject to the
disinfection requirements of Sections
300 and
518. (3-24-22)
a. Systems using only ground water that add
chlorine for the purpose of disinfection, as defined in Section
003, are subject to the following
requirements: (3-24-22)
i. Chlorinator and
chlorine contact tank capacity shall be such that the system is able to
demonstrate that it is routinely achieving four (4) logs (ninety-nine point
ninety-nine percent) (99.99%)) inactivation/removal of viruses. The required
effective contact time will be specified by the Department. This condition must
be attainable even when the plant design capacity coincides with anticipated
maximum chlorine demands. (3-24-22)
ii. A detectable chlorine residual shall be
maintained throughout the distribution system. (3-24-22)
iii. Automatic proportioning chlorinators are
required where the rate of flow or chlorine demand is not reasonably constant.
(3-24-22)
iv. Analysis for free
chlorine residual shall be conducted at a location at or prior to the first
service connection at least daily and records of these analyses shall be kept
by the supplier of water for at least one (1) year. A report of all daily
chlorine residual measurements for each calendar month shall be submitted to
the Department no later than the tenth day of the following month. The
frequency of measuring free chlorine residuals shall be sufficient to detect
variations in chlorine demand or changes in water flow. (3-24-22)
v. If gas chlorination equipment is provided,
a separate and ventilated room is required. (3-24-22)
vi. The Department may, in its discretion,
require a treatment rate higher than that specified in Subsection
552.04.a.i.
(3-24-22)
vii. When chlorine gas is
used, chlorine leak detection devices and safety equipment shall be provided
and equipped with both an audible alarm and a warning light.
(3-24-22)
viii. The Department may
require redundant chlorine pumping capabilities with automatic switchover for
systems with documented source water contamination problems and that lack
adequate storage to supply the system during a pump failure.
(3-24-22)
b. Systems
using only ground water that add chlorine for the purpose of maintaining a
disinfectant residual in the distribution system, when the source(s) is not at
risk of microbial contamination, are subject to the following requirements:
(3-24-22)
i. Automatic proportioning
chlorinators are required where the rate of flow or chlorine demand is not
reasonably constant. (3-24-22)
ii.
Analysis for free chlorine residual shall be made at a frequency that is
sufficient to detect variations in chlorine demand or changes in water flow.
(3-24-22)
c. Systems using
only ground water that add chlorine for other purposes, such as oxidation of
metals or taste and odor control, when the source(s) is known to be free of
microbial contamination, must ensure that chlorine residual entering the
distribution system after treatment is less than four (4.0) mg/L. The
requirements in Subsection
552.04.b.ii. also apply if
the system maintains a chlorine residual in the distribution system.
(3-24-22)
05.
Fluoridation. (3-24-22)
a.
Commercial sodium fluoride, sodium silico fluoride and hydrofluosilicic acid
which conform to the applicable American Water Works Association (AWWA)
Standards, incorporated by reference into these rules at Subsection
002.01, are acceptable. Use of
other chemicals shall be specifically approved by the Department.
(3-24-22)
b. Fluoride compounds
shall be stored in covered or unopened shipping containers. (3-24-22)
c. Provisions shall be made to minimize the
quantity of fluoride dust. Empty bags, drums, or barrels shall be disposed of
in a manner that will minimize exposure to fluoride dusts. (3-24-22)
d. Daily records of flow and amounts of
fluoride added shall be kept. An analysis for fluoride in finished water shall
be made at least weekly. Records of these analyses shall be kept by the
supplier of water for five (5) years. (3-24-22)
06.
Cross Connection Control Program -
Community Water Systems. The water purveyor is responsible through its
cross connection control program to take reasonable and prudent measures to
protect the water system against contamination and pollution from cross
connections through premises isolation, internal or in-plant isolation, fixture
protection, or some combination of premises isolation, internal isolation, and
fixture protection. Pursuant to Section
543, all suppliers of water for
community water systems shall implement a cross connection control program to
prevent the entrance to the system of materials known to be toxic or hazardous.
The water purveyor is responsible to enforce the system's cross connection
control program. The program will at a minimum include: (3-24-22)
a. An inspection program to locate cross
connections and determine required suitable protection. For new connections,
suitable protection must be installed prior to providing water service.
(3-24-22)
b. Required installation
and operation of adequate backflow prevention assemblies. Appropriate and
adequate backflow prevention assembly types for various facilities, fixtures,
equipment, and uses of water should be selected from the AWWA Pacific Northwest
Section Cross Connection Control Manual, the Uniform Plumbing Code, the AWWA
Recommended Practice for Backflow Prevention and Cross Connection Control
(M14), the USC Foundation Manual of Cross Connection Control, or other sources
deemed acceptable by the Department. The assemblies must meet the requirements
of Section 543 and comply with local
ordinances. (3-24-22)
c. Annual
inspections and testing of all installed backflow prevention assemblies by a
tester licensed by a licensing authority recognized by the Department. Testing
shall be done in accordance with the test procedures published by the
University of Southern California Foundation for Cross-Connection Control and
Hydraulic Research. See the USC Foundation Manual of Cross-Connection Control
referenced in Subsection
002.02. (3-24-22)
d. Discontinuance of service to any
structure, facility, or premises where suitable backflow protection has not
been provided for a cross connection. (3-24-22)
e. Assemblies that cannot pass annual tests
or those found to be defective shall be repaired, replaced, or isolated within
ten (10) business days. If the failed assembly cannot be repaired, replaced, or
isolated within ten (10) business days, water service to the failed assembly
shall be discontinued. (3-24-22)
07.
Cross Connection Control -
Non-Community Water Systems. All suppliers of water for noncommunity
water systems shall ensure that cross connections do not exist or are isolated
from the potable water system by an approved backflow prevention assembly.
Backflow prevention assemblies shall be inspected and tested annually for
functionality by an Idaho licensed tester, as specified in Subsections
552.06.c. and 552.06.e.
(3-24-22)
08.
Start-up
Procedures For Seasonal Systems Subject To Subsections
100.01.a., c., and d.
(3-24-22)
a. All seasonal system owners and
operators must demonstrate completion of a Department approved start-up
procedure, including start-up sampling, prior to serving water to the public.
The system owner or operator must submit information on a Department provided
or approved form that includes a statement certifying that the system owner or
operator followed proper start-up procedures. The form shall be submitted to
the Department within 30 (thirty) days following the system's start-up date.
(3-24-22)
b. The Department may
exempt any seasonal system from Subsection
552.08.a. if the entire
distribution system remains pressurized during the entire period that the
system is not operating, except that the systems that monitor less frequently
than monthly must still monitor during the vulnerable period designated by the
Department. The Department may exempt a seasonal system from Subsection
552.08.a. if the owner or
operator of the system meets all of the following conditions: (3-24-22)
i. Requests an exemption in writing to the
Department for approval; (3-24-22)
ii. Demonstrates a clean compliance history
as defined in Section
003 for a minimum of five (5)
years; (3-24-22)
iii. Has no
uncorrected significant deficiencies from the most recent sanitary survey; and
(3-24-22)
iv. Total coliform
samples submitted to a certified laboratory within 30 (thirty) days prior to
serving water to the public demonstrate the absence of total coliform.
(3-24-22)