[Amended 2-12-2020 by Ord. No. 2020.01.08-001]
This article is adopted pursuant to the following:
A. New Hampshire Administrative Rules Part Env-Dw 505, Backflow Prevention,
or subsequent rules.
B. The Dover Utilities Commission rules and regulations approved by
the Dover City Council. Under these rules and regulations, the Community
Services Department has the primary responsibility for protecting
the public water supply from the backflow and cross-contamination
of dangerous substances which would endanger the public health or
physically damage the public water system.
As used in this article, the following terms shall have the
meanings indicated:
AIR GAP
A physical separation sufficient to prevent backflow between
the free-flowing discharge end of the potable water system and any
other system. Physically defined as a vertical distance equal to twice
the diameter of the supply pipe but not less than one inch.
ATMOSPHERIC VACUUM BREAKER
A device which prevents backsiphonage by creating an atmospheric
vent when there is either a negative pressure or subatmospheric pressure
in a water system.
AUXILIARY WATER SUPPLY
Any water supply on or available to the premises other than
the purveyor's approved public potable water supply.
BACKFLOW
The flow of water or other fluids, mixtures or substances
into the distribution pipes of a potable water system from any source
other than the intended approved source of supply.
BACKPRESSURE
A condition in which the owner's system pressure is greater
than the supplier's system pressure.
BACKSIPHONAGE
The flow of water or other fluids, mixtures or substances
into the distribution pipes of a potable water system from any source
other than its intended source caused by the sudden reduction of pressure
in the public water system.
BAROMETRIC LOOP
A fabricated piping arrangement rising at least 35 feet at
its topmost point above the highest fixture it supplies. It is utilized
in water systems to protect against backsiphonage.
CONTAINMENT
A method of backflow prevention which requires a backflow
prevention device at the water service entrance.
CONTAMINANT
A substance that may impair the quality of the water, creating
a potential health hazard to the public.
CROSS-CONNECTION
Any actual or potential connection between the public water
system and any source of contamination or unapproved water source.
DOUBLE CHECK VALVE ASSEMBLY
An assembly of two independently operating, spring-loaded
check valves with tightly closing shut-off valves on each side of
the double check valve, plus properly located test cocks for the testing
of each check valve.
FIXTURE ISOLATION
A method of backflow prevention in which a backflow preventer,
such as a hose bib or an atmospheric vacuum breaker, is located to
correct a cross-connection at an in-plant location rather than at
a water service entrance. This protects the drinking water in the
building.
HOSE BIB VACUUM BREAKER
A device which is connected to a hose bib and which acts
as an atmospheric vacuum breaker. Not to be used under constant pressure.
OWNER
Any person who has legal title to, or license to operate
or habitat in, a property upon which a cross-connection inspection
is to be made or upon which a cross-connection may be present.
PERSON
Any individual, partnership, company, public or private corporation,
political subdivision or agency of the state, department, agency or
instrumentality of the United States, or any other legal entity.
PRESSURE VACUUM BREAKER
A device containing one or two independently operated, spring-loaded
check valves and an independently operated, spring-loaded air inlet
valve located on the discharge side of the check valve(s). The device
includes tightly closing shutoff valves on each side of the check
valve(s) and properly located test cocks for the testing of the assembly.
REDUCED PRESSURE PRINCIPLE BACKFLOW PREVENTER
An assembly consisting of two independently operating, spring-loaded
check valves with an automatically operating differential relief valve
located between the two check valves, tightly closing shutoff valves
on each side of the check valves, plus properly located test cocks
for the testing of the check valves and the relief valve.
RESIDENTIAL DUAL CHECK
An assembly of two spring-loaded, independently operating
check valves. Generally employed immediately downstream of the water
meter to act as a containment device in a single- or two-family residence.
WATER SERVICE ENTRANCE
That point in the owner's water system beyond the sanitary
control of the water supplier; generally considered to be the outlet
end of the water meter or where the water service first enters the
building.
WATER SUPERINTENDENT
The official, or his delegated representative, in charge
of the Community Services Department who is invested with the authority
and responsibility for the implementation of an effective cross-connection
control program and for the enforcement of the provisions of this
article.
The Water Superintendent shall be responsible for the protection
of the public potable water distribution system from contamination
or pollution due to the backflow or backsiphonage of contaminants
or pollution through the water service connection. If, in the judgment
of the Water Superintendent, an approved backflow prevention device
is required at the City of Dover's water service connection to any
customer's premises for the safety of the water system, the Water
Superintendent or his designated agent shall give notice, in writing,
to said customer to install an approved backflow prevention device
at each service connection to his premises. The customer shall, within
90 days, install the approved device or devices at his own expense.
Failure, refusal, or inability on the part of the customer to install
said device or devices within 90 days shall constitute grounds for
discontinuing water service to the premises until such device or devices
have been properly installed.
The Community Services Department recognizes the threat to the
public water system arising from cross-connections. All threats will
be classified by degree of hazard and will require the installation
of approved backflow prevention devices for high and low hazards.
A. Low degree of hazard. If backflow were to occur, the resulting effect
on the water supply would be a change in its aesthetic qualities.
The foreign substance must be nontoxic to humans.
B. High degree of hazard.
(1) If backflow were to occur, the resulting effect on the water supply
could cause illness or death if consumed by humans. The foreign substance
may be toxic to humans from either a chemical, bacteriological or
radiological standpoint. The effects of the contaminants may result
from short- or long-term exposure.
(2) Only the following types of backflow prevention devices may be used
for the containment of on-site contaminants for high- and low-hazard
situations, respectively:
(a)
High hazard.
[2]
Reduced pressure principal backflow preventer (RPZ).
[3]
Combination of the above.
(b)
Low hazard.
[2]
Pressure vacuum breaker (PVB).
[3]
Double check valve assembly (DCVA).
[4]
Reduced pressure principal backflow preventer (RPZ).
[5]
Combination of the above.
The Community Services Department shall not permit a cross-connection
within the public water system unless it is considered necessary and
cannot be eliminated.
A. Cross-connection permits that are required for each backflow prevention
device are obtained from the Community Services Department. A fee
will be charged for the initial permit and for the renewal of each
permit as found in the Fee Schedule.
B. Cross-connection permits shall be renewed every five years and are
nontransferable. Permits are subject to revocation and become immediately
revoked:
[Amended 2-12-2020 by Ord. No. 2020.01.08-001]
(1) If
the owner should change the type of cross-connection or degree of
hazard associated with the service type of device;
(2) Upon
replacement of the device with a new device; or
(3) Upon
change of ownership.
C. A permit is not required when fixture isolation is achieved with
the utilization of a nontestable backflow preventer in the case of
residential dual checks.
Any existing backflow preventer shall be allowed by the Community
Services Department to continue in service unless the degree of hazard
is such as to supersede the effectiveness of the present backflow
preventer, or unless an unreasonable risk to the public health results.
The Community Services Department will publish a list of fees
or charges. See Fee Schedule.
[Added 2-12-2020 by Ord.
No. 2020.01.08-001]
Violation of this article shall be subject to a fine as provided
in the City Fine Schedule.