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A basement bathroom sewage ejector pump is the most powerful and permanent solution for installing a full bathroom below grade. Unlike macerating upflush systems, an ejector pump uses a sealed sewage basin buried beneath the concrete slab to handle waste from:
- Toilet
- Shower
- Bathtub
- Sink
- Laundry (optional)
This guide covers how sewage ejector systems work, how to install them, code requirements, venting, pump sizing, discharge pipe rules, and more. All keywords you provided are integrated naturally.
What Is a Sewage Ejector Pump?
A sewage ejector pump is a submersible sewage pump placed in a buried pit that automatically grinds and pumps wastewater upward to your home’s main sewer line.
It is designed for full basement bathroom plumbing, including:
- installing a shower drain in the basement
- basement bathtub plumbing
- basement shower kit installations
- Freestanding tub on a concrete slab
- raised shower base for basement
This system is ideal when you want a permanent bathroom that functions just like one on the upper floors.
When Do You Need a Basement Bathroom Sewage Ejector Pump?
You need an ejector pump when:
- Your basement plumbing sits below the main house drain
- Gravity drainage is impossible
- You want a full bathroom with high-flow fixtures
- You need long-term, high-capacity waste removal
An ejector pump is mandatory for:
- Basement tub
- Basement shower
- Basement toilet
- Any below-grade bathroom requiring reliable drainage
Upflush macerators are great, but they cannot match the capacity of an ejector pump.
Key Components of an Ejector Pump System
A complete basement bathroom sewage ejector pump system includes:
- Sewage basin installation (pit)
- Submersible sewage pump
- Check valve installation
- Discharge pipe (usually 2-inch)
- Ejector pump vent pipe
- Sealed basin cover
- High water alarm (optional but recommended)
This entire unit sits below your concrete slab inside an excavated pit.
Excavating & Preparing the Sump Pit
Before installation, you must dig a pit for the basin.
Steps include:
- Excavating a sump pit at least 30″–36″ deep and 18″–24″ wide
- Removing concrete using a saw or jackhammer
- Digging soil until the required depth is reached
- Creating a stable gravel base for the basin
- Placing the basin so the top sits flush with the floor
The pit houses all waste from your bathroom fixtures.
Installing the Sewage Basin

A standard sewage pit holds 30 gallons, but larger basins are available for bigger bathrooms.
Important features:
- Heavy-duty polyethylene basin
- Gasketed and bolted sealed basin cover
- Inlet holes for bathtub, shower, and sink
- Vent connection
- Pump access opening
The sealed cover is crucial because it prevents:
- Sewer gas smell
- Moisture escape
- Insect entry
You cannot install a basement bathroom without a sealed basin; the code requires it.
Connecting Basement Fixtures to the Basin
Now you must run all fixture drains into the basin.
A. Shower Drain in Concrete Slab
To install a shower drain in a concrete slab for an ejector system:
- Dig a trench from the shower to the pit
- Install a P-trap
- Maintain proper slope
- Connect to the basin inlet
If your shower cannot be placed entirely below grade, use a raised shower base for a basement.
B. Basement Bathtub Plumbing
A tub drain connects to the basin through its own inlet. Use:
- Standard waste/overflow kit
- Correct slope
- Vent connection
C. Freestanding Tub on Concrete Slab
When installing a freestanding tub on a concrete slab, you have two options:
- Cut into the slab and connect directly to the basin
- Build a small platform to run drains above the floor
D. Sink & Laundry Drain
Basins often include an additional port for sink drainage or washing machines.
Installing the Submersible Sewage Pump
Your submersible sewage pump sits at the bottom of the basin.
Pump features include:
- 1/2 HP to 3/4 HP motors
- Float switch for automatic operation
- Solids-handling capability (up to 2-inch solids)
- Thermal overload protection
This pump activates when the basin fills with wastewater.
Discharge Line Requirements
The pump pushes waste out through a 2-inch discharge pipe, the industry standard.
Pipe rules include:
- Must include a check valve installation to prevent backflow
- Must tie into the main drain above grade
- May include a union for service access
- Must follow vertical lift requirements
Vertical lift/head height
Head height is the total distance the pump must push waste vertically.
Most pumps handle:
- 12–20 feet of vertical lift
- 100+ feet horizontal distance
Choosing the correct pump is essential for performance.
Venting the Ejector Pump
An ejector system needs proper venting through:
- A dedicated ejector pump vent pipe
- Tied into the main vent stack
- No AAV (Air Admittance Valve), since they are not allowed for sewage pits
Proper venting prevents siphoning, pressure buildup, and sewer gas odor.
Installing the Sealed Basin Cover
A sealed basin cover includes:
- Bolted lid
- Rubber gasket
- Inlet seals
- Pump cord grommet
- Vent pipe connection
Code requires the basin to be sealed because waste inside the tank is not macerated; it contains raw sewage.
High Water Alarm (Optional but Recommended)
A high water alarm warns you when the basin fills beyond normal levels.
Benefits:
- Prevents basement flooding
- Alerts you to pump failure
- Gives you time to shut off fixtures
Install it on the basin cover for best results.
Patching the Concrete After Installation
Once the pump, basin, and pipes are installed:
- Backfill trenches with gravel
- Compact soil around the basin
- Pour new concrete
- Smooth and level with the existing slab
This restores the basement floor and keeps the bathroom looking clean.
Sewage Ejector Pump vs Upflush Toilet
| Feature | Ejector Pump | Upflush Toilet |
| Digging required | Yes | No |
| Power | Strong | Moderate |
| Capacity | Entire bathroom | Toilet + sink + shower |
| Noise | Low | Moderate |
| Longevity | High | Medium |
| Best for | Permanent basement bathrooms | Quick or budget installs |
If you want a true full-function bathroom, a basement bathroom sewage ejector pump is the best option.
Conclusion
A basement bathroom sewage ejector pump is the most reliable and durable system for installing a complete bathroom below grade. From excavating a sump pit to sewage basin installation, discharge pipe sizing, check valve installation, and venting, every step ensures your bathroom works exactly like one on the upper floors.
With the ability to handle showers, tubs, toilets, and sinks, even a basement shower kit or freestanding tub on a concrete slab, an ejector pump is a long-term investment that adds comfort, value, and functionality to your home.

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