Sewage Ejector Pump Installation
Updated February 20, 2026
If you've got a basement bathroom, laundry room, or any fixture below the main sewer line, you need an ejector pump to push waste uphill to the sewer. This isn't the same as a sump pump -- ejector pumps handle solid waste and need a sealed, vented basin. It's a more involved install, and honestly, it's one of the plumbing jobs where most homeowners are better off hiring a pro. But if you've got the skills and the stomach for it, here's how it works.
Overview
If you've got a basement bathroom, laundry room, or any fixture below the main sewer line, you need an ejector pump to push waste uphill to the sewer. This isn't the same as a sump pump -- ejector pumps handle solid waste and need a sealed, vented basin. It's a more involved install, and honestly, it's one of the plumbing jobs where most homeowners are better off hiring a pro. But if you've got the skills and the stomach for it, here's how it works.
What to Know
Tools & Materials
- Sewage ejector pump (grinder or solids-handling)
- Sealed ejector basin (minimum 18x30)
- 2-inch discharge pipe and fittings
- Check valve (sewage rated)
- Vent pipe (2-inch, tied into existing vent stack)
- ABS or PVC drain pipe
- Wye or tee fittings for sewer tie-in
Step by Step
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Plan the layout
Map out which fixtures will drain into the ejector basin -- toilet, shower, sink, laundry. All drain lines from these fixtures need to run to the sealed basin. The discharge line runs from the pump up to the main sewer line above. Plan the vent pipe route to the roof.
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Excavate and set the basin
Break through the concrete floor, excavate for the basin, and set it on a gravel bed. The basin must be sealed with a gasketed lid -- no open pits for sewage systems. The inlet holes in the basin connect to the drain lines from each fixture.
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Run drain lines to the basin
Connect all below-grade fixture drains to the ejector basin using proper slope (1/4 inch per foot). Use proper fittings -- no 90-degree elbows on horizontal drain runs, use two 45s instead.
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Install the pump and discharge line
Set the pump in the basin with a check valve on the discharge. Run the 2-inch discharge pipe up and connect it to the main sewer line above grade using a wye fitting. The check valve prevents sewage from flowing back into the basin when the pump is off.
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Install the vent
The ejector basin must be vented -- a 2-inch vent pipe from the basin up through the roof or tied into the existing vent stack above the flood level of the highest fixture. Without proper venting, the system won't drain correctly and you'll get sewer gas in the basement.
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Seal, test, and inspect
Seal the basin lid. Fill the basin with water to test the pump activation and discharge. Check all connections for leaks. Schedule the plumbing inspection before closing up walls or patching the concrete.
Pro Tips
- Buy a pump with an alarm that sounds when the water level is too high. If the pump fails, you want to know before sewage backs up onto the floor.
- Size the pump for the vertical lift (called head pressure) from the basin to the sewer connection, plus the horizontal run. Undersizing the pump means it can't push waste far enough.
- A grinder pump handles everything but costs more. A solids-handling pump is cheaper but can jam on certain items. For a full bathroom with a toilet, a grinder pump is the safer bet.
Mistakes to Avoid
- Not venting the basin -- causes drain problems and sewer gas in the basement.
- Using a regular sump pump instead of a sewage-rated ejector pump.
- Not sealing the basin lid, which allows sewer gas to escape into the living space.
- Connecting the ejector discharge into the sewer line below the main flow level, which can cause backflow.
When to Call a Pro
Honestly, this is one job where hiring a plumber is the smart call for most homeowners. It involves breaking concrete, connecting to the sanitary sewer, venting through the roof, and passing an inspection. A licensed plumber handles the permit, does the work to code, and warranties it. The $1,500-$3,500 is well spent for the peace of mind.
Bottom Line
A sewage ejector system makes below-grade bathrooms and laundry possible, but it's a complex install with code requirements and permit obligations. If you're an experienced DIYer with plumbing knowledge, it's doable. For everyone else, this is a job for a licensed plumber.