Pumping Stations

PURPOSE: This rule specifies the minimum standards for the design of pumping stations that are part of wastewater collection and treatment systems. This rule is to be used with rules 10 CSR 20-8.110 through 10 CSR 20-8.210. It does not address all aspects of design, and the design engineer may refer to other appropriate reference materials so long as these minimum standards set forth in this rule are met. PUBLISHER’S NOTE: The secretary of state has determined that publication of the entire text of the material that is incorporated by reference as a portion of this rule would be unduly cumbersome or expensive. This material as incorporated by reference in this rule shall be maintained by the agency at its headquarters and shall be made available to the public for inspection and copying at no more than the actual cost of reproduction. This note applies only to the reference material. The entire text of the rule is printed here. (1) Applicability. Wastewater systems that utilize pumping stations shall be designed based on criteria contained in this rule, published standards, applicable federal and state requirements, standard textbooks, current technical literature, and applicable safety standards. In the event of any conflict between the above criteria, the requirement in this rule shall prevail. (A) This rule shall not apply to treatment units covered in 10 CSR 20-8.300. (B) This rule shall not apply to treatment units covered in 10 CSR 20-8.500. (2) Alternative Design. The department may approve an alternative design when it determines that the proposed alternative design is as effective or more effective than the requirements of this chapter and when compliance with the design requirements of this chapter would be unfeasible or impractical. The owner of a project proposing an alternative design must provide engineering justification to the department. The justification must— (A) Be requested in writing; (B) Be signed, sealed, and dated by a professional engineer licensed in Missouri; (C) Include an explanation of how compliance with a design requirement of this chapter is unfeasible or impractical; and (D) Include all pertinent facts, data, reports, and studies certifying the proposed alternative design will result in equivalent or improved effectiveness compared to the minimum design requirement in this chapter. (3) General. (A) Flood Protection. For flood protection, follow the provisions in 10 CSR 20-8.140(2)(B). (B) Access Road. For access roads to pump station sites, follow the provisions in 10 CSR 20-8.140(2)(D). (C) Safety. For safety, follow the applicable portions of 10 CSR 20-8.140(8). (D) Potable Water Sources. The distance between wastewater pumping stations and all potable water sources shall be at least fifty feet (50') in accordance with 10 CSR 23-3.010(1)(B). (E) Housed Wet Wells. Housed wet well ventilation shall be in accordance with 10 CSR 20-8.140(8)(J). (4) Design. (A) Structures. 1. Separation. Dry wells, including their superstructure, shall be completely separated from the wet well with gas-tight common walls. 2. Access. Suitable and safe means of access to dry wells and to wet wells shall be provided to persons wearing selfcontained breathing apparatus. (B) Pumps. 1. Multiple units. Multiple pumps shall be provided except for design average flows of less than fifteen hundred (1,500) gallons per day. 2. Electrical equipment. Electrical equipment shall be provided with the following requirements: A. Electrical equipment must comply with 10 CSR 208.140(7)(B); B. Utilize corrosive resistant equipment located in the wet well; C. Provide a watertight seal and separate strain relief for all flexible cable; D. Install a fused disconnect switch located above ground for the main power feed for all pumping stations; E. When such equipment is exposed to weather, it shall comply with the requirements of weather-proof equipment; enclosure NEMA 4; NEMA 4X, where necessary; and NEMA Standard 250-2014, published December 15, 2014. This standard shall hereby be incorporated by reference into this rule, as published by National Electrical Manufacturers Association, 1300 North 17th Street, Arlington, VA 22209. This rule does not incorporate any subsequent amendments or additions; F. Install lightning and surge protection systems; G. Install a one hundred ten volt (110 V) power receptacle inside the control panel located outdoors to facilitate maintenance; and H. Provide Ground Fault Circuit Interruption (GFCI) protection for all outdoor receptacles. (C) Controls. Water level controls must be accessible without entering the wet well. (D) Valves. Valves shall not be located in the wet well unless integral to a pump or its housing. (E) Wet Wells. Covered wet wells shall have provisions for air displacement to the atmosphere, such as an inverted and screened “j” tube or other means. (F) Ventilation. Interconnection between the wet well and dry well ventilation systems is not acceptable. For ventilation, follow the provisions in 10 CSR 20-8.140(8)(J). (G) Water Supply. There shall be no physical connection between any potable water supply and a wastewater pumping station, which under any conditions might cause contamination of the potable water supply. If a potable water supply is brought to the station, it shall comply with conditions stipulated under 10 CSR 20-8.140(7)(D). (5) Suction Lift Pumps. (A) Self-Priming Pumps. The combined total of dynamic suction lift at the “pump off” elevation and required net positive suction head at design operating conditions shall not exceed twenty-two feet (22'). (B) Vacuum Priming Pumps. Vacuum priming pump stations shall be equipped with dual vacuum pumps capable of automatically and completely removing air from the suction lift pump. (C) Wet Well Access. Wet well access shall not be through the equipment compartment. Access shall be provided in accordance with paragraph (4)(A)2. of this rule. (6) Submersible Pump Stations. Submersible pump stations shall meet the applicable requirements under section (4) of this rule, except as modified in this section. (A) Pump Removal. Submersible pumps shall be readily removable and replaceable without personnel entering, dewatering, or disconnecting any piping in the wet well. (B) Valve Chamber and Valves. Valves required under subsection (4)(D) of this rule shall be located in a separate valve chamber. 1. Access. A minimum access hatch dimensions of twentyfour inches by thirty-six inches (24" x 36") shall be provided. For access, follow the provisions in paragraph (4)(A)2. of this rule. 2. Portable pump connection. A portable pump connection on the discharge line with rapid connection capabilities shall be provided. (7) Alarm Systems. Alarm systems with an uninterrupted power source shall be provided for pumping stations. (8) Emergency Operation. Pumping stations shall be capable of operating during emergencies to prevent the discharge of raw wastewater. In addition to the required emergency means of operation and a storage/detention basin or tank, at least one (1) of the following shall be provided: (A) For a pump station serving a wastewater treatment facility with a design average flow of one hundred thousand (100,000) gallons per day or greater, a storage capacity for two- (2-) hour retention of the peak hourly flow; (B) For a pump station serving a wastewater treatment facility with a design average flow of less than one hundred thousand (100,000) gallons per day, a storage capacity for four- (4-) hour retention of the peak hourly flow; or (C) With sufficient engineering justification, designers may propose an alternative method to address emergency operations. At a minimum, this includes a reasonable amount of retention along with a dedicated generator of sufficient capacity capable of automatic start-up during power outages. All emergency equipment must be designed such that its operations can be tested on a regular schedule. Where independent electrical feeds are used for emergency power, each separate electrical feed shall be capable of starting and operating the pump station at its rated capacity. (9) Force Mains. (A) Design. Force main system shall be designed to withstand all pressures (including water hammer and associated cyclic reversal of stresses), and maintain a velocity of at least two feet (2') per second. (B) Installation. For installation follow the provisions in 10 CSR 20-8.120(3)(A). (C) Protection of Water Supplies. For separation between water mains and sanitary sewer force mains, follow the provisions in 10 CSR 20-8.120(5). (D) Locator wire. For locator wire, follow the provisions in 10 CSR 20-8.125(5)(A)5. AUTHORITY: section 644.026, RSMo 2016.* Original rule filed Aug. 10, 1978, effective March 11, 1979. Amended: Filed June 15, 2018, effective Feb. 28, 2019. Amended: Filed June 14, 2024, effective Jan. 30, 2025. *Original authority: 644.026, RSMo 1972, amended 1973, 1987, 1993, 1995, 2000, 2012, 2014.