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Outdoor Sump Pump Station

Purpose

Outdoor Sump Pump Stations are used when gravity alone won't allow the system to drain to the discharge area. A sump pump must lift the water to a higher point, to allow gravity to continue moving water away.

Important Notes

1. Chamber Assembly

A. Couple Chamber Components

Couple chamber extension to chamber tee using a split coupler to achieve the chamber length specified in the job description. Fasten using zip ties.

B. Drill Drainage Holes

Using a 3/8" drill bit, drill 6 holes (one on top, one on bottom, two on each side) equally spaced on the outside of the chamber. Continue these holes for every rib.

C. Install End Caps

Install a single-wall end cap using a split coupler on both ends of the chamber. Drill approximately 15 holes near the bottom of each end cap using a 3/8" drill bit.

2. Excavation

A. Excavate the Pit

Excavate a hole approximately 30" wide, 30" deep, and the length of the chamber specified in the job description, plus 1 foot of overdig.

B. Install Filter Fabric

Encapsulate the excavation using standard 4 oz. filter fabric. Put fabric down first so that you can use the gravel to make minor adjustments to level.

C. Level Gravel Base

Lay 4" of gravel as a base and level it using a laser level. Use gravel to set the elevation of the top of the chamber:

  • Recessed ~3" when using a grate
  • Flush with yard when using a solid lid

D. Dig Power Cable Trench

Dig a trench for a 4" PVC sleeve to house the power cables, which exit from the chamber riser to the outdoor outlet location specified in the job description.

3. Equipment and Plumbing Installation

A. Connect Drainage Pipes

Plumb system drainage pipes into the end caps of the chamber, using:

  • 5" hole saw for 4" pipes
  • 7" hole saw for 6" pipes

Note: No sealant required around pipe entries.

B. Backfill Chamber Void

Backfill the void around the chamber with 1" clean stone, up to the top of the chamber. Ensure the top of the chamber is level.

C. Install Power Cable Sleeve

Use a 5" hole saw to core a hole in the chamber riser. Insert a 4" SCH 40 PVC sleeve about 1.5" into the riser for power cable routing. Route this sleeve pipe to the specified outdoor outlet location, and use an elbow to extend it approximately 2" above grade.

D. Underground Electrical (If Required)

If underground electrical cable is required from the outlet location to the house, utilize the same trench that the PVC sleeve is in if possible, and leave 3 feet of tail at the outdoor outlet location.

E. Position the Pump

Place the pump at the bottom of the chamber. Center it within the riser and ensure it sits level.

F. Install Pump Discharge

Install the pump discharge pipe, plumbing it out of the riser toward the discharge trench if alignment allows. Use a PVC Union or Fernco to ensure future pump replacement is easy. Use pressure rated PVC.

G. Install Heater Ring

Place a heater ring in the chamber, 1–1.5 feet from the pump.

H. Route Power Cables

Pull the power cables (pump and heater) through the power sleeve and leave about 18" of slack (tag end) above ground. If using an extension cable, apply dielectric grease, then wrap the plug in electrical tape.

I. Secure Cables

Coil and secure the power cables on top of the pump using zip ties. Ensure cables don't interfere with the float switch operation.

J. Install Access Cover

Fasten the chamber access lid or grate.

4. Backfill

A. Clean Chamber

Critical: Before backfilling, clean out ALL debris from the chamber. If there are pieces, they will clog the pump and it will fail.

B. Cover with Fabric

Cover the top of the drainage stone with 4 oz. filter fabric.

C. Final Soil Backfill

Backfill remaining 6"–10" with soil to match the surrounding grade.

5. Discharge Line

A. Install Discharge Piping

Critical: Ensure the discharge line (1.5" or 2" flexible PVC Sch 40) drains completely after the pump shuts off.

  • Slope the line to create an apex so that when the pump shuts off, the line drains out both ends fully (into the station chamber and out the day-light end of line)
  • LINE MUST NOT HOLD WATER AFTER PUMP SHUTS OFF, BECAUSE THE LINE WILL FREEZE DURING THE WINTER AND BURN OUT THE PUMP OTHERWISE
  • Bury the line 7-12" as needed
  • Do not use a check valve
  • Do not discharge into a structure or pipe that traps water

B. Daylight Discharge

Day-light the line in a 5-foot dry creek bed for dispersal.

C. System Testing

If failure of the system would result in water damage to the client's home, the system must be tested by filling it with a garden hose after installation.

6. Material Specifications

Chamber Components:

  • 15" culvert pipe
  • 15" culvert tees
  • 15" single-wall end caps
  • 15" split couplers
  • 1.5" flexible PVC Schedule 40
  • Zip Ties

Access Lid or Grate:

  • 15" Poly-Lok pipe lids or grates

Pumps ("Little Giant" brand from Menards - use only the pump specified in the job description):

  • 1/2 HP, 2" discharge
  • 3/4 HP 1.5" discharge

Power Cable:

  • Single-pump station: 10/2 direct burial cable
  • Dual-pump system: 10/3 direct burial cable
  • 10ft 14 gauge extension cords

Basin Heaters ("Farm Innovators" brand from Amazon):

  • Basins 4–8 ft: Model C250
  • Basins 9–12 ft: Model C500