1. (a) House sewer. The sewer from the building's plumbing to the septic tank shall be constructed of cast iron, ductile iron, polyvinyl chloride (PVC) Schedule 40, SDR 26 or other material approved by the executive director. The slope of the sewer shall be no less than 1/8 inch fall per foot of pipe. The sewer stub out should be as shallow as possible to facilitate gravity flow. A two-way cleanout plug must be provided between building's plumbing and the septic tank. All fittings used on this section shall be sanitary type. An additional cleanout plug shall be provided every 50 feet (where applicable, near 90 degree bends) on long runs of pipe and may be of the single sanitary type. This sewer shall have a minimum inside diameter of three inches.

2. (b) Pump tanks. Pump tanks may be necessary when the septic tank outlet is at a lower elevation than the disposal field. All requirements in §285.32(a)(1)(D)-(H) of this title (relating to Criteria for Sewage Treatment Systems) are also applicable to pump tanks. The pump tank shall be constructed in accordance with the following specifications:

   1. (1) Pump tank criteria. When effluent must be pumped to a disposal area, an appropriate pump shall be placed in a separate water-tight tank or chamber. A check valve may be required if the disposal area is above the pump tank. The pump tank shall be equipped to prevent siphoning. The tank shall be provided with an audio and visual high water alarm. If an electrical alarm is utilized the power circuit shall be separate from the pump. Batteries may be utilized for back-up power supply only. All electrical components shall be approved by Underwriters Laboratories (UL).
   2. (2) Pump tank sizing. Pump tanks shall be sized for one-third day of flow above the alarm-on level. Reserve capacity (capacity above the alarm-on level) may be reduced to four hours average flow when pump tank is equipped with multiple pumps.
   3. (3) Pump specifications. A single pump may be used for flows equal to or less than 1,000 gallons per day. Dual pumps are required for flows greater than 1,000 gallons per day. A dual pump system shall have the "alarm on" level below the "second pump on" level, and shall have a lock-on feature in the alarm circuit so that once it is activated it will not go off when the second pump draws the liquid level below the "alarm on" level. All audio and visual alarms shall have a manual "silence" switch. Pump switch-gear shall be selected such that both pumps shall operate as the first pump on an alternating basis. All pumps shall be rated by the manufactures for pumping sewage or sewage effluent.
   4. (4) Electrical wiring. All electrical wiring shall be in accordance with the most recent edition of the National Electric Code. Connections shall be in approved junction boxes and all external power wiring shall be in approved electrical conduit, buried and terminated at a main circuit breaker panel or sub-panel. All electrical components should have an electrical disconnect within direct vision. Electrical disconnects must be weatherproof (approved for outdoor use) and have maintenance lockout provisions.
3. (c) Grease interceptors. Grease interceptor shall be used on kitchen waste-lines from institutions, hotels, restaurants, schools with lunchrooms, and other places that may discharge large amounts of greases and oils to the OSSF. Grease interceptors shall be structurally equivalent to the requirements established for septic tanks under §285.32(a)(1)(D)-(H) of this title (relating to Criteria for Sewage Treatment Systems). The interceptor shall be installed near the plumbing fixture that discharges greasy wastewater and shall be easily accessible for cleaning. Grease interceptors shall be cleaned out periodically to prevent the discharge of grease to the disposal system. Grease interceptors shall be properly sized and installed in accordance with the most recent requirements of the Uniform Plumbing Code or other prevailing code.

4. (d) Holding tanks. Tanks shall be constructed in accordance with subsection (b)(1) of this section and shall be structurally equivalent to the requirements established for septic tanks under §285.32 (a)(1)(D)-(H) of this title (relating to Criteria for Sewage Treatment Systems). Inlet (no outlet shall be provided) fittings are required. A baffle is also not required. Holding tanks shall be used only on lots where no other methods of sewage disposal are feasible (these holding tank provisions do not apply to portable toilets). All holding tanks shall be equipped with a visual and audible alarm to indicate when the tank has been filled to within 75% of its rated capacity. A port with its smallest dimension being 15 inches or greater shall be provided in the tank lid for inspection, cleaning, and maintenance. This port shall be accessible from the ground surface and must be easily removable and watertight.

   1. (1) Minimum capacity. Holding tank minimum capacity shall be sufficient to store the estimated or calculated daily wastewater flow for a period of one week (wastewater usage rate in gallons/day X 7 days).
   2. (2) Location. Holding tanks shall be installed in an area readily accessible to the pump truck under all weather conditions, and at a location that meets the minimum distance requirements in accordance with §285.91(10) of this title (relating to Tables).
   3. (3) Maintenance. A scheduled pumping contract with a licensed waste transporter, holding a valid registration with the executive director, must be provided to the permitting authority before any holding tanks are installed. Records of such activities must be retained for five years.
5. (e) Composting toilets. Composting toilets will be approved by the executive director provided the system has been tested and certified under NSF International Standard 41 (1983).
6. (f) Condensation. If condensate lines are plumbed directly into a OSSF, the increased water volume must be accounted for (added to the usage rate) in the system planning materials.

Source Note:The provisions of this §285.34 adopted to be effective February 5, 1997, 22 TexReg 1114.