All water service connections are subject to the installation
of backflow prevention assemblies in order to safeguard the public
drinking water supply. The requirements of this chapter are in addition
to any requirements of federal, state or local law.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
California Administrative Code, Title 17, Sections 7583 et seq.,
are adopted and incorporated by reference herein, insofar as the same
are applicable to the protection of the water supply of the district.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
Definitions used in this chapter, unless the context requires
otherwise, are as follows:
"Air gap separation - approved"
means a physical break between the supply pipe and a receiving
vessel. The air gap shall be at least double the diameter of the supply
pipe, measured vertically above the top rim of the receiving vessel,
and in no case less than one inch.
"Backflow"
refers to the flow of water or other fluid or substance or
combination or mixture thereof into the potable water supply distribution
pipes from any source or sources other than the intended source of
supply.
"Check valve - approved"
means a check valve that is drip-tight in the normal direction
of flow when the inlet pressure is at least one psi and the outlet
pressure is zero. The check valve shall permit no leakage in a direction
reverse to the normal flow. The closure element (e.g. clapper, poppet
and other design) shall be internally weighted or otherwise internally
loaded to promote rapid and positive closure. An approved check valve
is only one component of an approved backflow prevention assembly,
i.e., pressure vacuum breaker, double check valve assembly or reduced
pressure principle assembly.
"Cross-connection"
means any unprotected actual or potential connection or structural
arrangement between a public or a consumer's potable water system
and any other source or system through which it is possible to introduce
into any part of the potable system any used water, industrial fluid,
gas, or substance other than the intended potable water with which
the system is supplied. Bypass arrangements, jumper connections, removable
sections, swivel or change over devices and other temporary or permanent
devices through which or because of which backflow can or may occur
are cross-connections.
"Double check valve assembly - approved"
means an assembly composed of two single, independently acting,
approved check valves, including tightly closing shut-off valves located
at each end of the assembly and fitted with properly located test
cocks.
"Reclaimed water"
means wastewater which as a result of tertiary treatment
is suitable for uses other than potable use.
"Reduced pressure principle backflow prevent assembly - approved"
means a device containing two independently acting approved
check valves, together with a hydraulically operating, mechanically
independent pressure relief valve located between the check valves
and at the same time below the first check valve. The unit shall include
properly located test cocks and tightly closing shutoff valves at
each end of the assembly.
"Service connection"
means the terminal end of a service connection from the public
potable water system, i.e., where the water purveyor loses jurisdiction
and sanitary control over the water at its point of delivery to the
consumer's water system. If a meter is installed at the end of the
service connection, then the service connection shall mean the downstream
end of the meter.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
The consumer's system shall be open for inspection at all reasonable
times to authorized representatives of the district to determine whether
cross-connections or sanitary hazards, including violations of this
chapter exist.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
Every water service connection to premises on which any of the following conditions exist or are planned shall be protected against backflow from the premises by suitable backflow prevention assemblies as specified in Section
11.14.060:
(1) An auxiliary water supply which is not certified by the State Health
Department as a domestic water supply; or
(2) The handling of any substance under pressure in such a manner as
to permit possible ultimate entry into the district's system; or
(3) Internal cross-connections that are not permanently correctable;
or
(4) Intricate plumbing arrangements which make it impractical or impossible
to ascertain whether or not cross-connections exist.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
The type of backflow prevention assemblies required shall be
as follows, depending upon the degree of hazard which exists:
(1) At the service connection to any premises where there is an auxiliary
water supply handled in a separate piping system with no known cross-connections
the district's system shall be protected by an approved double check
valve assembly. If such service is subject to any back siphonage,
the district's system shall be protected by an approved reduced pressure
principle backflow prevention assembly.
(2) At the service connection to any premises on which a substance that
would be objectionable but not necessarily hazardous to health, if
introduced into the district's system, is handled so as to constitute
a cross connection, the district's system shall be protected by an
approved reduced pressure principle backflow prevention assembly.
(3) At the service connection to any premises on which an auxiliary water
supply with cross-connections, the district's system shall be protected
by an approved reduced pressure principle backflow prevention assembly.
(4) At the service connection to any premises on which any material dangerous
to health or toxic substances in toxic concentration is or may be
handled under pressure, or in a situation subject to siphoning, the
district's system shall be protected by an approved air gap separation.
If the approved air gap separation requirement cannot reasonably be
met, an approved reduced pressure principle backflow prevention assembly
may be substituted if acceptable to both the district and the Marin
County health department.
(5) At the service connection to any sewage treatment plant or sewage
pumping station, the district's system shall be protected by an approved
air gap separation. If the approved air gap separation requirement
cannot reasonably be met, an approved reduced pressure principle backflow
prevention assembly may be substituted if acceptable to the district,
the Marin County health department, and the State Department of Public
Health.
(6) At the service connection to any property where reclaimed water is
provided, the district may also require that its potable system be
protected by a backflow prevention assembly.
(7) At the service connection to any premises to which an irrigation
service is supplied, the district's system shall be protected by an
approved double check valve assembly:
(a) If such service is subject to any back siphonage, or if fertilizers,
herbicides, pesticides, or any other hazardous substance will be injected
into the consumer's piping system, the district's system shall be
protected by an approved reduced pressure principle backflow prevention
assembly.
(b) The district may also require that its system be protected by a backflow
prevention assembly appropriate to the degree of hazard to the public
drinking water supply determined by the district to exist at any service
connection not covered in subsection (a) of this section.
(c) Any protective assembly required in this section shall be a model
approved by the district. In general, a double-check valve assembly
or a reduced pressure principle backflow prevention assembly to be
approved by the district shall be listed on the State Department of
Public Health's list of approved backflow prevention assemblies.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
All backflow prevention assemblies shall be installed in a horizontal
position a minimum of twelve inches above finished grade and in accordance
with all district rules and regulations.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
It shall be the duty of the consumer, at any premises where
backflow protection assemblies are required, to furnish, install,
maintain and have tested by a certified tester, the assemblies at
his own expense. A test shall be made as soon as is practical after
installation and at least once a year thereafter; however, the district
may require more frequent tests if extreme hazards exist or successive
inspections disclose repeated failures in the operation of any assembly.
The consumer shall notify the district when the assembly has been
installed. Assemblies shall be repaired, overhauled, or replaced at
the expense of the consumer whenever they are found to be unapproved
or defective. Records of such tests, repairs and overhaul shall be
kept by the consumer and shall be promptly forwarded to the district
by the consumer.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)
Water service to any premises may be discontinued by the district, pursuant to Chapter
11.28 if a backflow prevention assembly, required by this chapter is not installed, tested and/or maintained; or if any deficiency is found in the installation or operation of a backflow prevention assembly; or if it is found that a backflow prevention assembly has been removed, or bypassed. Service shall not be restored until such conditions or defects are corrected. Any cost to the district for the investigation and abatement of a deficiency shall be included in the charges due before service is restored.
(Ord. 236 §1, 1983; Ord. 314 §2, 1990)