Chicago basements can have two kinds of pit, and the pumps in them fail in different ways. A sump pump lifts groundwater from the drain tile around the foundation, while an ejector pump lifts sewage from a basement bathroom, laundry or floor drain set too low to reach the sewer by gravity. Call Chicago Plumbworks for sump pump repair or ejector pump replacement and we’ll set up a visit with a licensed plumber, whether it’s a bungalow basement or a garden unit in a two-flat. If the pit has already overflowed and water is spreading across the basement floor, the cleanup and the cause get handled together.
Sump pump or ejector pump: which one is in your pit?
| Sump pump | Ejector pump | |
|---|---|---|
| What it moves | Groundwater from the drain tile and the soil around the foundation | Wastewater and sewage from fixtures below the sewer: toilet, shower, laundry, sometimes the floor drain |
| The pit | An open or covered basin in the floor | A sealed basin with a vent pipe, since it holds sewage |
| The pump | Built for water and small debris | A sewage pump, built to pass solids, up to 2 inches on common models |
| Where the water goes | Out of the building through a discharge pipe | Up into the building drain, or an overhead line, and on to the sewer |
| What you notice when it quits | Water rises out of the pit and spreads across the floor | Basement toilets and drains slow, then the pit backs up into the basement |
A quick way to tell them apart: a pit with a sealed lid and a pipe climbing from it into the wall or ceiling is an ejector pit. If there’s sewage in it, treat it as one and leave the lid on.
In older houses the footing drains were often tied straight into the house sewer. The Village of Palatine’s flooding guidance recommends disconnecting them and putting in a sump pump, which takes groundwater off the same line that backs up in storms.
Ejector pits in garden units
In a two-flat or three-flat, the garden unit’s bathroom, kitchen and laundry can sit lower than the sewer pipe that leaves the building. Chicago’s plumbing code sends a drain that can’t reach the sewer by gravity into a tightly covered, vented sump, with a pump to lift it into the building’s drain. That’s the ejector pit, and a garden unit relies on it in ways the floors above don’t:
- The tenant depends on it without seeing it. Every flush and shower in the unit goes into the pit. When the pump stops, the toilet still flushes, right up until the pit is full.
- It may take storm water too. If the unit’s floor drain runs to the pit, or the building has an overhead sewer, any water that reaches the basement drains goes to the pump, so it works hardest in the worst weather.
- Wipes are its weak point. The MWRD asks everyone to flush nothing but toilet paper, because wipes, including ones labeled flushable, clog pipes and damage equipment. In a garden unit, the pump is the first equipment they meet.
- The pit alarm has to be where someone hears it. A high-water alarm behind a locked utility room door helps no one.
For a landlord, the useful setup is an alarm the tenant can hear, a breaker labeled for the pump, and a tenant who knows to stop using the fixtures and call when it sounds.
Why do sump and ejector pumps fail?
A pump that stops moving water has a short list of suspects:
- Power. A tripped breaker, an outage or a dead outlet. Zoeller’s manuals also warn against long or light extension cords, which can’t deliver enough voltage to the motor.
- The float. It’s the switch that starts and stops the pump. One caught on the pit wall, its own cord or debris either never starts the pump or never lets it stop, and Zoeller points to a stuck float first when a pump won’t shut off.
- The check valve. It keeps pumped water from dropping back into the pit. When it fails, the water just lifted runs back down and the pump goes again.
- Buildup in the pit. Silt and gravel in a sump pit; grease, wipes and grit in an ejector pit. Zoeller’s maintenance list includes checking the basin for buildup that blocks the float or the intake.
- More water than it can move. FEMA lists torrential rain overloading a pump, alongside pump failure and power loss, as the ways a pit floods a basement.
- A worn-out motor. A pump that hums without moving water may have a jammed impeller or a motor at the end of its life, and the plumber checks which.
Why does the ejector act up after a city sewer backup?
A street sewer backup can leave the garden unit’s ejector pit in bad shape even after the water’s gone. If the unit’s floor drain runs to the pit, the backup brings in grit, grease and debris that foul the float or pack the intake. If the pit overflowed, the pump, the float and the alarm all sat under sewage, and the pit has to be cleaned out before anyone can tell what still works. Ask for the pit, the float and the check valve to be looked at during the same visit as the backup.
Do you need a battery backup?
For a sump pump in a basement you want dry, yes. The storms that fill a sump pit are the same ones that knock the power out, and FEMA’s flood guidance calls for sump pumps with backup power, from batteries or a generator. A battery backup is a second pump in the same pit on its own float switch, and it goes to work when the water reaches that float. Some models also sound an alarm when something needs attention.
Test a sump pump now and then by pouring a bucket of water into the pit. It should start, empty the pit and shut off by itself. Don’t try that with an ejector pit.
An ejector pit is a different case. Ask the plumber what backup power suits the pump you have. If the answer is a generator, it runs outdoors; the CDC says never inside the house, the basement or the garage. In a building with an overhead sewer, that one pump drains the whole basement, so plan its backup first.
What does replacing a pump involve?
The visit starts with diagnosis, because a new pump on a stuck float or a bad check valve fails the same way the old one did.
- Find out why it stopped: power at the outlet and breaker, the float, the check valve and the discharge line.
- Open the pit. On an ejector pit that means pumping it down and taking off the sealed lid.
- Pull the old pump and match the new one to the job. That’s a sump pump for groundwater or a sewage pump rated for solids, sized for how high and how far it has to push.
- Replace the worn parts around it, often the check valve and, on an ejector, the lid gasket.
- Seal it, run it through full cycles with water and test the alarm.
How long that takes depends on what turns up. Swapping a sump pump in an open pit is a smaller job than an ejector in a sealed basin under a finished garden-unit floor. A cracked basin or a corroded discharge line adds to it too. The plumber can tell you once the pit is open.
What moves the cost of an ejector pump replacement
- The pump. A sewage pump built to pass solids costs more than a sump pump, and a bigger lift calls for more horsepower.
- The basin. Reusing a sound one, or replacing a cracked or undersized pit.
- The parts around it. Check valve, lid, gasket and vent connection, when they’re worn.
- Access. A pit under a finished floor, in a closet or behind a tenant’s furniture.
- Add-ons. An alarm or backup power put in on the same visit.
Ask for the price in writing before the old pump comes out. You only pay for work you agreed to.