Grinder pump backing up or overflowing
Short answer
Stop all water use now. Keep people and pets away from sewage and the equipment. Call the utility immediately if it handles alarms on your system or maintains your pump; otherwise call your pump service provider. Leave the lid and panel closed.
A grinder pump overflows when the basin has used up its emergency storage: the pump stopped moving sewage, the house kept sending it, and the level climbed past the alarm to the inlet pipe and the lowest fixture. Nearly every backup starts as an alarm that was silenced and then ignored, or an outage that outlasted the tank.
What to do in the next ten minutes, why continued water use makes it worse, and what we find when we open the station.
Safe steps, in order
Nothing here opens the panel or the basin. If a step does not clear it, stop and make the call.
Step 1: Shut the water off at the fixtures, or at the house valve
Every drop that goes down a drain now arrives in a full basin. If someone in the house is likely to forget, close the main shut-off valve. The BCSS Keen user guide warns that continued water use during an alarm can cause a plumbing blockage.
Step 2: Leave the equipment alone
Stay back from the lid, panel and any standing water. Silencing a horn can wait; it will not stop the backup.
Step 3: Keep clear of the sewage
Inside, close off the room. Outside, keep children and pets off wet ground near the lid. Raw sewage is a health hazard, and the ground around an overflowing station is also where the electrical supply enters.
Step 4: Call the utility if it asks, then request service
Do not wait for the alarm to clear while sewage is coming back in. Call the utility if it services the station or handles alarm calls on your system. Otherwise call your pump service provider now.
Why it backs up
The cushion is finite. E-One puts the emergency storage of its stations at roughly a day, conditional on water usage, and wants repairs done inside that window. MAWSS gives Mobile homeowners the same rough figure for most tanks. The BCSS Keen station is a 24-inch-wide tank five feet deep. All of those numbers assume a household that has stopped using water. A family that keeps showering and flushing through an alarm uses the whole cushion in hours.
When the level reaches the inlet, sewage stands in the building drain. The lowest fixture, a shower, floor drain or tub, is where it appears first. At the station, the lid vent is the pressure relief, so a basin that overflows outside usually does so at the lid, and BCSS notes that a grinder basin overflows from its lid vent when power is out.
Possible causes
An outage, a mechanical fault or a blocked line can all interrupt pumping.
- Lost power or a tripped breaker during a storm, with the house still in use. Without power the pump can neither pump nor alarm (Keen, Barnes).
- A jammed grinder: wipes, rags, grease or floss stopped the cutter and the overload opened (Keen, Myers).
- A failed float or level sensor, including sensors coated in grease (Keen, BCSS).
- A check valve stuck or installed backwards, or a closed valve at the station or the street, so the pump ran but could not discharge (Keen, Myers, Liberty).
- A failed pump: motor flooded through a bad seal, a torn stator on a progressive cavity pump, or a short (Keen, Barnes, Myers).
- A blocked or broken discharge line between the basin and the main, which also shows up as wet ground along the pipe route.
- Rainwater entering the basin faster than the pump could move it (E-One).
What we check and do
Restore pumping first: power and current, the overload and start components, the level controls, the cutter and inlet, the check valve and discharge valves. Then why the storage ran out: how long the alarm had been on, whether the panel was silenced earlier, whether water use continued. Then the damage: whether the motor took in water, whether the basin needs pumping out and cleaning, and whether the inlet or discharge line is blocked. Where the pump has failed on a BCSS system, BCSS supplies and installs the replacement; elsewhere, replacement follows your utility's rule.
After a power outage
If sewage is backing up during or after an outage, stop household water use and call for help immediately. A timing rule for an alarm alone does not apply once sewage is coming up. Stay away from equipment that has been flooded.
When it is an emergency
It already is. Sewage inside a home is a health and property emergency, and sewage on the ground near a station carries the same risk. Stop the water, keep clear, call. For smoke, fire or active sparking, move away and call 911.
Still not right? Ask from here
Your name, a way to reach you and what the pump is doing. That is all we need to start. Town and utility are optional.
Sewage backing up or overflowing? Stop using water and call now: (251) 850-8031. On a utility-owned pump, call your utility first.
Questions people ask
Why is my grinder pump overflowing?
The pump stopped moving sewage, the household kept producing it, and the basin's emergency storage ran out. Behind the stop: lost power, a jammed cutter, a failed float or level sensor, a stuck check valve or closed valve, or a failed pump. Rainwater entering the basin can do it too.
Sewage is backing up into my shower. Is that the grinder pump?
On a grinder system, usually yes: the basin is full and the building drain is standing. It can also be a clog in the house drain between the shower and the basin. Either way, stop all water and call; a technician can tell within minutes by looking at the basin level.
How long can a grinder pump be off before it backs up?
E-One describes a 24-hour emergency storage capacity depending on water usage, and MAWSS says most tanks hold about a day of normal flow. With water use stopped, most households get through a day. With normal use, a few hours.
Can I use the toilet during an alarm?
Keep it to the minimum. E-One's instruction is to limit water during an alarm, and the BCSS user guide warns that continued use can block the plumbing. One flush is a gallon or more into a basin that has already called for help.
Sources and facts
- E-One owners guide p.5: 24-hour emergency storage capacity, depending on water usage; repairs should be carried out within that period; minimize wastewater going in; limit water during an alarm. E/One Owners Guide (LM000403 Rev G), eone.com/… (read 2026-11-04)
- MAWSS hurricane page: most tanks hold about 24 hours of normal flow. MAWSS Hurricane Preparation, www.mawss.com/… (read 2026-11-04)
- BCSS Keen user guide p.13-14: stop water use immediately and call your utility provider; continued use can cause a plumbing blockage; pump cannot pump or alarm without power; station tank 24 in by 60 in (p.1). BCSS-distributed Keen KPCGSL21 grinder station manual, www.baldwincountysewer.com/… (read 2026-11-04)
- BCSS User Tips: a grinder basin overflows from its lid vent when power is out. BCSS User Tips, www.baldwincountysewer.com/… (read 2026-11-04)
- Barnes OGV manual p.3: pump cannot dispose of wastewater or provide an alarm signal without power. Barnes OGVF/OGVH installation manual (Form 108890 Rev X), d1pkofokfruj4.cloudfront.net/… (read 2026-11-04)
- Keen O&M p.9: solids lodged in inlet; float switch defective or restricted; check valve stuck closed or backwards; ground water entering basin. Myers p.8: clogged grinder with overload and high-water alarm; check valve flapper stuck; valve at street off. Liberty p.10: check valve stuck or backwards; valve closed. Keen Pump O&M-KPCG (May 2022), keenpump.com/…; Pentair Myers WG(X)20 owner's manual 23833A744, www.pentair.com/…; Liberty Pumps ProVore PRG-Series installation manual 2399000, www.libertypumps.com/… (read 2026-11-04)
- Barnes OGV manual p.12: insufficient capacity includes stator damaged/torn, check valve stuck/backwards, shut-off valve closed, cutter jammed. Barnes OGVF/OGVH installation manual (Form 108890 Rev X), d1pkofokfruj4.cloudfront.net/… (read 2026-11-04)
- E-One owners guide p.6: alarm when it rains means rainwater may be getting into the system; after a power failure the alarm may activate until the unit clears; call if still on more than an hour after power is restored. E/One Owners Guide (LM000403 Rev G), eone.com/… (read 2026-11-04)
- From January 1, 2026 all grinder pumps on the BCSS system must be purchased from BCSS and installed by BCSS. BCSS FAQ: alarm over 15 minutes, contact BCSS or a plumber. GSU: contact the Board any time the red light is on. BCSS Grinder Pumps page, www.baldwincountysewer.com/grinder-pumps; BCSS Grinder Pump FAQs, www.baldwincountysewer.com/…; Gulf Shores Utilities grinder pump page, www.gulfshoresutilities.com/grinder-pump (read 2026-11-04)