Nevada Administrative Code › Chapter 444 - Sanitation › SEWAGE DISPOSAL › Individual Sewage Disposal Systems › Section 444.804 - Construction of septic tank

Current through June 11, 2024
1. Plans for a
				septic tank which have not been previously approved by the health authority
				must be submitted to the health authority for approval. The plans must show all
				dimensions, reinforcing, structural calculations and such other pertinent data
				as may be required pursuant to NAC 444.804 to 444.810, inclusive. A septic tank
				must be constructed of solid durable materials, and must not be subject to
				excessive corrosion or decay. Acceptable materials include concrete, coated
				steel, polyethylene, fiberglass and any other material approved by the health
				authority.
2. A septic tank must
				have two compartments. The capacity of the inlet compartment must be not less
				than 2/3 of the total capacity of the tank. The inlet compartment must be at
				least 3 feet in width and 5 feet in length. The depth of the liquid in the
				inlet compartment must be not less than 30 inches or more than 72 inches. The
				secondary compartment must have a minimum capacity of 300 gallons and a maximum
				capacity equal to 1/3 of the total capacity of the septic tank. If the septic
				tank has a total capacity of more than 1,500 gallons, the secondary compartment
				must be 5 feet or more in length.
3. Adequate access must be provided into each
				compartment to facilitate inspection and cleaning of the tank. Each compartment
				must have at least one manhole to provide access into the compartment. A
				manhole must have a minimum diameter of 20 inches. If the inlet compartment is
				longer than 12 feet, an additional manhole must be provided over the baffle or
				partition wall.
4. An inlet pipe
				and an outlet pipe must each be at least 4 inches in diameter. The top of the
				tee or baffle for both the vented inlet and the vented outlet must extend at
				least 4 inches above the level of the liquid. The bottom of the tee or baffle
				for both the vented inlet and vented outlet must extend at least 12 inches
				below the level of the liquid. The invert of the inlet pipe must be at least 2
				inches above the invert of the outlet pipe.
5. A manufactured septic tank must be
				permanently and legibly marked as to the manufacturer, total tank capacity,
				liquid capacity and general location of the manufacturing firm.
6. A partition or baffle between compartments
				must be made of solid, durable material, must extend at least 4 inches about
				the liquid level, and must be vented to allow for the free passage of gas
				between the compartments. A down-turned 90-degree inverted fitting, which is at
				least 4 inches in diameter, must be installed on the side of the baffle or
				partition for the inlet compartment. The inverted fitting must be set so that
				the bottom of the fitting is placed at a level that is equal to not less than
				50 percent or more than 75 percent of the height of the liquid level in the
				tank. A baffle or partition may not be made of wood.
7. A septic tank must be structurally
				designed to withstand all anticipated loads of dirt or other substances, must
				be installed so that the tank is level and must be installed on a solid bed.
				The cover of a septic tank must be capable of supporting a load of dirt of not
				less than 300 pounds per square foot.
8. All aggregates fine and coarse, other than
				lightweight aggregate, must conform to specifications outlined by the
Standard Specifications for Public Works Construction
adopted
				by reference pursuant to NAC 444.7825.
9. Aggregates must be free of deleterious
				substances which may react with oxidized hydrogen sulfide. Aggregates must be
				graded in such a manner as to produce a homogeneous concrete mix. All materials
				must be accurately weighed at a central batching facility for mixing.
10. All cement must be Portland cement
				conforming to the
Standard Specifications for Public Works
				Construction
adopted by reference pursuant to NAC 444.7825. Cement
				content must be sufficient to produce a minimum strength of 3,000 PSI, or other
				design strengths required.
11. All
				concrete must be handled from the mixer or transport vehicle to the place of
				final deposit in a continuous manner, as rapidly as practicable, and without
				segregation or loss of ingredients, until the approved construction is
				completed. Each pour must be compacted by mechanical internal or
				external-vibrating equipment. Duration of the vibration cycle must be limited
				to the time necessary to produce satisfactory consolidation without causing
				objectionable segregation.
12. All
				reinforcing steel, including welded wire mesh, must be of the size and in the
				location as shown on the plans. The reinforcing steel must be sufficiently tied
				to withstand any displacement during the pouring operation. All bars must be
				made of intermediate or hard graded billet steel. The health authority may
				inspect the tank reinforcing steel before any concrete is poured.
13. The side walls of a septic tank must
				extend at least 9 inches above the level of the liquid. The interior ceiling of
				the septic tank must be at least 2 inches above the top of the tee or baffle
				for the vented inlet and the top of the tee or baffle for the vented
				outlet.
14. A septic tank must be
				watertight. A manufacturer of a septic tank shall test the tank for
				watertightness by one of the following methods:
(a) Water testing by sealing the outlets,
				filling the septic tank to its operational level and allowing the tank to stand
				not less than 8 hours or more than 10 hours. If, after this period, there is a
				measurable loss of water, the tank must be refilled and allowed to stand for an
				additional 8 to 10 hours. If, after the second period, there is a measurable
				loss, the tank must be rejected. A septic tank may not be rejected solely
				because of the appearance of damp spots on the exterior of the tank. A tank
				that has been rejected must be repaired and tested before it may be used in an
				individual sewage disposal system.
(b) Vacuum testing by sealing all of the
				inlets, outlets and accesses and introducing a vacuum of 4 inches of mercury.
				If the vacuum drops during the first 5 minutes, the vacuum must be brought back
				up to 4 inches of mercury. If the septic tank fails to hold the vacuum at 4
				inches of mercury during the second 5-minute period, the tank must be rejected.
				A tank that has been rejected must be repaired and tested before it may be used
				in an individual sewage disposal system.
(c) An alternative testing procedure approved
				by the health authority.