Storage Tanks Flashcards
Is the tank located within 500 ft of a WWTP or an area spray-irrigated with treated effluent or sludge disposal?
290.43(b)(1)(A)(i-iii),(B)
Location of clearwells, standpipes, and ground storage and elevated tanks.
(1) No public water supply elevated storage or ground storage tank shall be located:
(A) within 500 feet of any;
(i) municipal or industrial sewage treatment plant;
(ii) land which is spray irrigated with sewage treatment plant effluent; or
(iii) land on which sewage treatment plant sludge, septic tank sewage sludge, or biosolids is applied
Is the tank secured by an intruder resistant fence?
290.43(e)
Facility security. All potable water storage tanks and pressure maintenance facilities must be installed in a lockable building that is designed to prevent intruder access or enclosed by an intruder-resistant fence with lockable gates. Pedestal-type elevated storage tanks with lockable doors and without external ladders are exempt from this requirement. The gates and doors must be kept locked whenever the facility is unattended.
If below ground storage present:
Located > 50 ft from sewer/septic tank?
Located > 150 ft from septic tank soil absorption system?
290.43(b)(1)(A)(i-iii),(B)
Location of clearwells, standpipes, and ground storage and elevated tanks.
(1) No public water supply elevated storage or ground storage tank shall be located:
(A) within 500 feet of any;
(i) municipal or industrial sewage treatment plant;
(ii) land which is spray irrigated with sewage treatment plant effluent; or
(iii) land on which sewage treatment plant sludge, septic tank sewage sludge, or biosolids is applied
Roof vent adequate? Is it screened?
290.43(c)(1)
Roof vents shall be gooseneck or roof ventilator and be designed by the engineer based on the maximum outflow from the tank. Vents shall be installed in strict accordance with current AWWA standards and shall be equipped with approved screens to prevent entry of animals, birds, insects and heavy air contaminants. Screens shall be fabricated of corrosion-resistant material and shall be 16-mesh or finer. Screens shall be securely clamped in place with stainless or galvanized bands or wires and shall be designed to withstand winds of not less than tank design criteria (unless specified otherwise by the engineer).
Is tank roof equipped w/ adequate 30” opening (24” if 30” on side), w/ 4” roof curbing, and locked?
290.43(c)(2)
All roof openings shall be designed in accordance with current AWWA standards. If an alternate 30-inch diameter access opening is not provided in a storage tank, the primary roof access opening shall not be less than 30 inches in diameter. Other roof openings required only for ventilating purposes during cleaning, repairing or painting operations shall be not less than 24 inches in diameter or as specified by the licensed professional engineer. An existing tank without a 30-inch in diameter access opening must be modified to meet this requirement when major repair or maintenance is performed on the tank. Each access opening shall have a raised curbing at least four inches in height with a lockable cover that overlaps the curbing at least two inches in a downward direction. Where necessary, a gasket shall be used to make a positive seal when the hatch is closed. All hatches shall remain locked except during inspections and maintenance.
Is the overflow adequate? Equipped w/ cover that closes with ≤ 1/16” gap
290.43(c)(3)
Overflows shall be designed in strict accordance with current AWWA standards. If the overflow terminates at any point other than the ground level, it shall be located near enough and at a position accessible from a ladder or the balcony for inspection purposes. The overflow(s) shall be sized to handle the maximum possible fill rate without exceeding the capacity of the overflow(s). The discharge opening of the overflow(s) shall be above the surface of the ground and shall not be subject to submergence. The discharge opening shall be covered with a gravity-hinged and weighted cover, an elastomeric duckbill valve, or other approved device to prevent the entrance of insects and other nuisances. When the tank is not overflowing, the cover shall close automatically and fit tightly with no gap over 1/16 inch.
Is the tank equipped w/ a proper liquid level indicator?
290.43(c)(4)
All clearwells and water storage tanks shall have a liquid level indicator located at the tank site. The indicator can be a float with a moving target, an ultrasonic level indicator, or a pressure gauge calibrated in feet of water. If an elevated tank or standpipe has a float with moving target indicator, it must also have a pressure indicator located at ground level. Pressure gauges must not be less than three inches in diameter and calibrated at not more than two-foot intervals. Remote reading gauges at the owner’s treatment plant or pumping station will not eliminate the requirement for a gauge at the tank site unless the tank is located at the plant or station.
Are inlet and outlet connections located to prevent short-circuiting?
290.43(c)(5)
Inlet and outlet connections shall be located so as to prevent short-circuiting or stagnation of water. Clearwells used for disinfectant contact time shall be appropriately baffled.
Are tank and associated appurtenances tight against leakage? Are all tank walls separate from other plant units
containing process water?
290.43(c)(6)
Clearwells and potable water storage tanks shall be thoroughly tight against leakage, shall be located above the groundwater table, and shall have no walls in common with any other plant units containing water in the process of treatment. All associated appurtenances including valves, pipes, and fittings shall be tight against leakage.
Is there a way to remove silt and other deposits?
290.43(c)(7)
Each clearwell or potable water storage tank shall be provided with a means of removing accumulated silt and deposits at all low points in the bottom of the tank. Drains shall not be connected to any waste or sewage disposal system and shall be constructed so that they are not a potential agent in the contamination of the stored water. Each clearwell or potable water storage tank must be designed to drain the tank.
Is the tank properly maintained? Is it in satisfactory condition?
290.43(c)(8)
All clearwells, ground storage tanks, standpipes, and elevated tanks shall be painted, disinfected, and maintained in strict accordance with current AWWA standards. However, no temporary coatings, wax grease coatings, or coating materials containing lead will be allowed. No other coatings will be allowed which are not approved for use (as a contact surface with potable water) by the United States Environmental Protection Agency, NSF International (NSF), or United States Food and Drug Administration. All newly installed coatings must conform to American National Standards Institute/NSF (ANSI/NSF) Standard 61 and must be certified by an organization accredited by ANSI.
Inspection ladder provided?
290.43(c)
Design and construction of clearwells, standpipes, ground storage tanks, and elevated tanks. All facilities for potable water storage shall be covered and designed, fabricated, erected, tested, and disinfected in strict accordance with current American Water Works Association (AWWA) standards and shall be provided with the minimum number, size and type of roof vents, man ways, drains, sample connections, access ladders, overflows, liquid level indicators, and other appurtenances as specified in these rules. The roof of all tanks shall be designed and erected so that no water ponds at any point on the roof and, in addition, no area of the roof shall have a slope of less than 0.75 inch per foot.
Drains properly connected (not connected to any waste or sewage disposal system)?
290.43(c)(7)
Each clearwell or potable water storage tank shall be provided with a means of removing accumulated silt and deposits at all low points in the bottom of the tank. Drains shall not be connected to any waste or sewage disposal system and shall be constructed so that they are not a potential agent in the contamination of the stored water. Each clearwell or potable water storage tank must be designed to drain the tank.
