Current through August 31, 2023
The materials and designs used for finished water storage
structures shall provide stability and durability as well as protect the
quality of the stored water. Finished water storage structures shall be
designed to maintain water circulation and prevent water stagnation. Steel
structures and facilities such as steel tanks, standpipes, reservoirs, and
elevated tanks shall be designed and constructed in accordance with applicable
AWWA Standards, incorporated by reference into these rules at Subsection
002.01. Other materials of
construction are acceptable when properly designed to meet the requirements of
Section 544.
(3-24-22)
01.
Sizing and
Isolation Requirements. (3-24-22)
a.
Storage facilities shall have sufficient capacity, as determined from
engineering studies that consider peak flows, fire flow capacity, and analysis
of the need for various components of finished storage as defined under the
term "Components of Finished Water Storage" in Section
003. The requirement for storage
may be reduced when the source and treatment facilities have sufficient
capacity with standby power to supply peak demands of the system.
(3-24-22)
b. All storage structures
which provide pressure directly to the distribution system, such as elevated
storage structures or ground level storage structures with associated pumping
systems, shall be designed so they can be isolated and drained for cleaning or
maintenance without causing a loss of pressure in the distribution system.
(3-24-22)
02.
Location. Storage facilities shall be located in a manner that
protects against contamination, ensures structural stability, protects against
flooding, and provides year-round access by vehicles and equipment needed for
repair and maintenance. (3-24-22)
a. If the
bottom elevation of a storage reservoir must be below normal ground surface, it
shall be placed above the seasonal high ground water table. (3-24-22)
b. Non-potable mains and services, standing
water, and similar sources of possible contamination must be kept at least
fifty (50) feet from any partially buried or below-ground storage structure or
facility, except that non-potable mains and services constructed of potable
water class pipe are allowed as close as twenty (20) feet from a partially
buried or below-ground storage structure or facility. Partially buried or
below-ground storage structures or facilities shall be located a minimum of
fifty (50) feet from the nearest property line. (3-24-22)
c. No public water supply storage tank shall
be located within five hundred (500) feet of any municipal or industrial
wastewater treatment plant or any land which is spray irrigated with wastewater
or used for sludge disposal. (3-24-22)
d. The top of a partially buried storage
structure shall not be less than two (2) feet above normal ground surface.
(3-24-22)
e. Ground-level or
above-ground storage structures or facilities shall be located a minimum of
twenty (20) feet from the nearest property line and a minimum of twenty (20)
feet from any potential source of contamination. (3-24-22)
03.
Protection from
Contamination. All finished water storage structures shall have suitable
watertight roofs which exclude birds, animals, insects, and excessive dust. The
installation of appurtenances, such as antennas, shall be done in a manner that
ensures no damage to the tank, coatings or water quality, or corrects any
damage that occurred. (3-24-22)
04.
Protection from Trespassers. Fencing, locks on access manholes,
and other necessary precautions shall be provided to prevent trespassing,
vandalism, and sabotage. (3-24-22)
05.
Drains. No drain on a water
storage structure may have a direct connection to a sewer or storm drain. The
design shall allow draining the storage facility for cleaning or maintenance
without causing loss of pressure in the distribution system.
(3-24-22)
06.
Overflow. Overflow pipes of any storage structure or facility
shall discharge to daylight in a way that will preclude the possibility of
backflow to the reservoir and, where practical, be provided with an expanded
metal screen installed within the pipe that will exclude rodents and deter
vandalism. The overflow pipe shall be of sufficient diameter to permit waste of
water in excess of the filling rate. The overflow shall discharge over a
drainage inlet structure or a splash plate and, when practical, discharge at an
elevation between twelve (12) and twenty-four (24) inches above the receiving
surface. (3-24-22)
a. When an internal
overflow pipe is used on above-ground tanks, it shall be located in the access
tube. (3-24-22)
b. The overflow for
ground-level, partially buried, or below-ground storage structures or
facilities shall have a vertical section of pipe at least two (2) pipe
diameters in length and either: (3-24-22)
i.
Be screened with a twenty-four (24) mesh non-corrodible screen installed within
the pipe when practical or an expanded metal screen installed within the pipe
plus a weighted flapper valve or check; or (3-24-22)
ii. Be an equivalent system acceptable to the
Department. (3-24-22)
07.
Access. Finished water
storage structures shall be designed with reasonably convenient access to the
interior for cleaning and maintenance. At least two (2) manholes shall be
provided above the waterline at each water compartment where space permits, as
determined by the Department. One (1) manhole may be allowed on smaller tanks
on a case-by-case basis. (3-24-22)
a. The
following access requirements apply to above-ground and ground-level storage
structures. Each access manhole shall be framed a minimum of four (4) inches
above the surface of the roof at the opening. The actual height above the
surface of the roof must be sufficient to prevent incidental contamination from
snow accumulation, storm water runoff or accumulation, irrigation water, or
other potential sources of contamination. (3-24-22)
b. The following access requirements apply
to, partially buried or below-ground storage structures. Each access manhole
shall be elevated a minimum of twenty-four (24) inches above the surface of the
roof or the ground level, whichever is higher. The actual height above the
surface of the roof or the ground level must be sufficient to prevent
incidental contamination from snow accumulation, storm water runoff or
accumulation, irrigation water, or other potential sources of contamination.
(3-24-22)
c. Each manhole shall be
fitted with a solid water tight cover designed to prevent the entrance of
contaminants. Each cover shall be hinged only on one (1) side and shall have a
locking device. Unless otherwise approved by the Department based on
documentation provided by the design engineer, each cover shall have a framed
opening with the lid extending down around the frame at least two (2) inches,
and the frame shall be at least four (4) inches high.
(3-24-22)
08.
Vents. Finished water storage structures shall be vented. The
overflow pipe shall not be considered a vent. Open construction between the
sidewall and roof is not permissible. Vents shall: (3-24-22)
a. Prevent the entrance of surface water and
rainwater and extend twelve (12) inches above the roof. (3-24-22)
b. Exclude birds and animals.
(3-24-22)
c. Exclude insects and
dust, as much as this function can be made compatible with effective venting.
(3-24-22)
d. On ground-level,
partially buried, or below-ground structures, open downward with the opening at
least twenty-four (24) inches above the roof or the ground level and covered
with twenty-four (24) mesh non-corrodible screen. The screen shall be installed
within the pipe at a location least susceptible to vandalism.
(3-24-22)
e. On above-ground tanks
and standpipes, open downward, and be fitted with twenty-four (24) mesh or
similar non-corrodible screen. (3-24-22)
09.
Roof and Sidewall. The roof
and sidewalls of all water storage structures must be watertight with no
openings except properly constructed vents, manholes, overflows, risers,
drains, pump mountings, control ports, or piping for inflow and outflow.
Particular attention shall be given to the sealing of roof structures which are
not integral to the tank body. (3-24-22)
a.
Any pipes running through the roof or sidewall of a metal storage structure
must be welded, or properly gasketed. In concrete tanks, these pipes shall be
connected to standard wall castings which were poured in place during the
forming of the concrete. (3-24-22)
b. Openings in the roof of a storage
structure designed to accommodate control apparatus or pump columns shall be
curbed and sleeved with proper additional shielding to prevent contamination
from surface or floor drainage. (3-24-22)
c. The roof of the storage structure shall be
sloped to facilitate drainage. Downspout pipes shall not enter or pass through
the reservoir. Parapets, or similar construction which would tend to hold water
and snow on the roof, will not be approved unless adequate waterproofing and
drainage are provided. (3-24-22)
d.
Reservoirs with pre-cast concrete roof structures must be made watertight with
the use of a waterproof membrane or similar product.
(3-24-22)
10.
Construction Materials. Materials used in storage facility
construction shall meet the requirements for water contact surfaces set forth
in Subsection 501.01.
Porous materials such as wood or concrete block are not acceptable for use in
storage construction. (3-24-22)
11.
Protection from Freezing. Finished water storage structures and
their appurtenances, especially the riser pipes, overflows, and vents, shall be
designed to prevent freezing which will interfere with proper functioning.
(3-24-22)
12.
Internal
Catwalk. Every catwalk over finished water in a storage structure shall
have a solid floor with sealed raised edges, designed to prevent contamination
from shoe scrapings and dirt. (3-24-22)
13.
Silt Stops. Removable silt
stops shall be provided to prevent sediment from entering the reservoir
discharge pipe. (3-24-22)
14.
Grading. The area surrounding a ground-level, partially buried, or
below-ground structures shall be graded in a manner that will prevent surface
water from standing within fifty (50) feet of it. (3-24-22)
15.
Coatings and Cathodic
Protection. Proper protection shall be given to metal surfaces by paints
or other protective coatings, by cathodic protective devices, or by both.
(3-24-22)
16.
Disinfection. Storage facilities shall be disinfected in
accordance with AWWA Standard C652, incorporated by reference into these rules
at Subsection 002.01.
Two (2) or more successive sets of samples, taken at twenty-four (24) hour
intervals, shall indicate microbiologically satisfactory water before the
facility is placed into operation. (3-24-22)
17.
Abandonment. All unused
subsurface storage tanks shall be removed and backfilled, or abandoned by
extracting residual fluids and filling the structure with sand or fine gravel.
(3-24-22)
