NR 110.14(10)(b)4.a. a. All valving shall be accessible without entry into the wet well or dewatering the wet well.

NR 110.14(10)(b)4.b. b. If a grinder pump station discharges to a common pressurized sewer, a redundant check valve shall be provided. All valves including redundant check valves shall be installed at the grinder pump station. If a grinder pump station discharges to a gravity sewer, the redundant check valve is not required.

NR 110.14(10)(b)5. 5. ‘Ventilation.’ All grinder pump stations shall be vented to the atmosphere either from the wet well or from the service lateral.

NR 110.14(10)(b)6. 6. ‘Accessibility.’ No permanent ladders or steps shall be provided in the wet wells.

NR 110.14(10)(b)7. 7. ‘Pump size.’ All grinder pumps shall have a minimum 1¼-inch pump inlet opening and discharge piping.

NR 110.14(10)(b)8. 8. ‘Velocity.’ A minimum velocity of 61 centimeters (2 feet) per second shall be maintained in the discharge piping during pump operation.

NR 110.14(10)(b)9. 9. ‘Separation.’ A minimum separation distance of 25 feet shall be maintained between the grinder pump lift station and a private well or any other well subject to ch. NR 812. A minimum separation of 200 feet shall be maintained between the grinder pump station and a community water system well in accordance with ch. NR 811.

NR 110.14(10)(b)10. 10. ‘Alarm.’ Audible and visual high water alarm system shall be provided.

NR 110.14(10)(b)11. 11. ‘Electrical.’

NR 110.14(10)(b)11.a. a. The motor control unit shall be located outside the wet well.

NR 110.14(10)(b)11.b. b. All junction boxes shall be located outside the wet well, and shall meet the requirements of weather proof equipment. Electrical supply, control and alarm circuits shall be designed to allow disconnection at the junction box, without destroying the conduit-seal.

NR 110.14(10)(b)11.c. c. Level controls using float type displacement switches shall be suspended in the wet well to facilitate maintenance.

NR 110.14(10)(b)12. 12. ‘Explosion prevention.’

NR 110.14(10)(b)12.a. a. In order to reduce the potential for ignition of explosive gases in submersible grinder pump lift stations, one of the following conditions shall be met: the low water level alarm shall be set such that the pump motor will remain totally submerged at all times; the pump motor shall be rated explosion proof in accordance with NEC requirements of Class I, Group D, Division 1 locations; or the motor shall be listed as safe and appropriate for residential use by the Underwriters Laboratories, Inc.

NR 110.14(10)(b)12.b. b. In order to reduce the potential for ignition of explosive gases in non-submersible grinder pump lift stations with non-explosion proof pump motors, the pump motor shall be completely isolated from the wet well atmosphere in a separate gas tight housing.

NR 110.14(11) (11) Effluent pumps. The department may approve the duplex and simplex effluent pump lift stations for septic tank effluent in accordance with the applicable requirements of subs. (9) and (10), respectively.

NR 110.14(12) (12) Emergency operation.

NR 110.14(12)(a) (a) General. Provisions for emergency operation of lift stations shall be provided to prevent the discharge of raw or partially treated sewage to a surface water or to a ground surface and to prevent sewage backups into basements.

NR 110.14(12)(b) (b) Lift station requirements. One of the following provisions shall be made to insure continued operation of each lift station:

NR 110.14(12)(b)1. 1. An on-site generator, with automatic switching and starting equipment may be installed. The generator shall have sufficient capacity to meet the total electrical demands of the pumps, controls, and auxiliary equipment.

NR 110.14(12)(b)2. 2. An on-site gasoline or diesel engine driven pump, with automatic switching and starting equipment may be installed. The pump shall have a capacity equal to or greater than the lift station peak design pumping rate.

NR 110.14(12)(b)3. 3. A portable generator may be available for use at the lift station. The generator shall have sufficient capacity to meet the total electrical demands of the pumps, controls, and auxiliary equipment. Electrical connections shall be accessible without maintenance personnel having to enter the lift station.

NR 110.14(12)(b)4. 4. A portable pump with a pumping capacity equal to or greater than the lift station peak design pumping rate may be available for use at the lift station. Quick disconnect fittings shall be used to connect the portable pump to the suction and the discharge line, and shall be accessible without maintenance personnel having to enter the lift station.

NR 110.14(12)(b)5. 5. The lift station electrical system may be connected to 2 independent electrical transmission routes which receive power from the same electrical grid network which supplies power to the lift station service area.

NR 110.14(12)(b)6. 6. The lift station may be equipped with a holding facility which has a capacity to hold the average design flow for a minimum period of 24 hours.

NR 110.14(12)(c) (c) Grinder pump and effluent pump lift stations.

NR 110.14(12)(c)1. 1. Emergency operation of duplex grinder pump and effluent pump lift stations which serve more than 3 residential units shall be provided by one of the methods described in par. (b).

NR 110.14(12)(c)2. 2. Emergency operation provisions for duplex grinder pump and effluent pump lift stations may be waived for those stations which serve homes with private water supply systems provided it is demonstrated to the department that the lift station wet well has the capacity to hold the residual water volume of the private water system.

NR 110.14 History History: Cr. Register, November, 1974, No. 227, eff. 12-1-74; r. and recr. Register, February, 1983, No. 326, eff. 3-1-83; correction in (2) (a) 3. made under s. 13.93 (2m) (b) 7., Stats., Register, September, 1995, No. 477; correction in (2) (a) 3. was made under s. 13.93 (2m) (b) 7., Stats., Register, May, 2001, No. 545; CR 09-123: am. (1) (b) and (2) (b) 3., r. and recr. (2) (a) 3. and (3) to (5), renum. (6) and (7) to be (9) and (12) and am., cr. (6) to (8), (10) and (11) Register July 2010 No. 655, eff. 8-1-10.