TL;DR: If your sump pump won't start, the fault is almost always in one of five places. Check power, the float, the pump body, the check valve, and the discharge line, in that order. Unplug it first, and expect debris or a blocked line rather than a dead motor.
Your sump pump does nothing for months. Then one week in November it gets asked to run for three days straight.
Now is the time to find out whether it still can, while the pit is dry and nobody is panicking. The whole thing takes about twenty minutes, in the order manufacturers use in their own troubleshooting tables.
Start with power, and unplug before you touch anything
Most pumps that seem dead are not. They have lost power somewhere between the breaker and the plug, and that is the fastest thing on this list to rule out.
Cut the power first
Standing water and electricity share a pit, so kill the power before anything else. Unplug it at the outlet, or shut off the breaker. Nothing else here happens until that's done.
Then check the three usual suspects
This is the boring part, and also the most common one:
- A plug worked loose from the piggyback float connection
- A ground fault outlet tripped and nobody noticed
- A breaker is sitting half thrown rather than fully off
Look at the cord while you're down there
Zoeller's installation instructions say to secure the power cord away from the float switch mechanism, and there's a good reason for that. A cord wrapped around a float pins the switch in one position.
A pump that hums but moves no water is a different problem from one that does nothing at all. The first points at the impeller or a stuck check valve. The second points at power or the switch.
Check the float for free movement
The float is where most residential pumps fail. Usually it isn't broken, though. It's just stuck.
What free movement actually means
Liberty Pumps sets out three conditions for a wide-angle float:
- Enough clearance to the basin wall
- Free movement through its full travel
- Nothing touching the pump or the piping at any point in that travel
If you need to move the float, use dry wood or plastic, never metal. Liberty warns against metal or anything conductive inside a live pit, which is the other reason the power comes off first.
What settles in the bottom of the pit
Zoeller asks owners to check the pit often for debris that gets in the float's way. Gravel, drywall dust from an old renovation, root fibre, it all ends up in a sump.
Any of it can park a float at the wrong height. Scoop what's there before you run the next check.
Run a water test, not a hand test
Lifting the float by hand only tells you the switch closes. It says nothing about whether the pump can move water, and that's the part that matters in November.
How to run the test
Liberty lists a monthly test, and it's a simple one. Pour enough water into the pit to bring the pump on when it wouldn't normally run, then watch the full cycle:
- It starts on its own
- It pulls the level down to its normal off point
- It shuts down without help
Do that twice. A pump that starts once and won't restart is telling you something, usually a thermal overload or a switch on its way out.
What to listen for
Grinding or rattling usually means debris has reached the impeller. If it runs on at a low water level, the float isn't reaching its off position.
📞 If it won't complete a cycle, that's worth a call now rather than mid-storm. Call or text us at (604) 897-4989.
Look at the check valve and its vent hole
The check valve stops water in the discharge pipe from falling back into the pit. When it fails, the pump usually still runs, which is what makes this one easy to miss.
Stuck open or stuck closed
Stuck closed, the pump runs and delivers nothing. Stuck open, the same column of water comes back every cycle and the pump short cycles all night.
Check valves are directional. One installed backwards during an old repair will pass a visual inspection and fail every time the pump runs.
The vent hole most people miss
Zoeller specifies a vent hole of roughly 5 mm (3/16 inch) in the discharge pipe, below the check valve. It purges trapped air so the pump can't air lock, and it needs cleaning now and then.
Block that hole and the pump hums, moves nothing, then works fine the moment somebody shakes the pipe. It's common enough that Zoeller answers it in its own support material.
Walk the discharge line to where it ends
The last check is outside. Liberty's troubleshooting table puts a blocked or restricted discharge line near the top of the reasons a pump runs without clearing the pit. It names ice specifically.
Follow the pipe from the wall out
Start at the rim joist and walk it to the outlet. You're looking for:
- A crushed or kinked section
- A joint that's come apart
- A screen packed with leaf litter
- Anything the last landscaping job buried
Then look at where the water lands
A discharge that empties beside the foundation is back in the pit within the hour. That's why a pump can run constantly while the level never drops.
Where the line ties into a perimeter drain or storm connection, that tie-in is a code question rather than a weekend project.
Where this stops being a homeowner job
Everything above is looking and testing. It all stays on your side of the line because nothing gets opened, rewired or cut.
Here's where it stops being yours:
- A breaker that trips again after a reset, or an outlet with no power
- Opening the pump housing
- Cutting or re-routing discharge pipe
- Any tie-in to a perimeter drain or storm line
Two more belong to us. A pit that fills faster than the pump can empty it is a sizing problem, not a fault. And a basement that's flooded once needs the cause found, not just a new pump.
Plenty of homeowners in South Surrey find the real cause is a failed water line rather than groundwater at all.
📞 If a check sends you past that line, we'll take it from there. Call or text (604) 897-4989 for a free quote.
A pump that passes all five checks will run when the rain arrives
Power, float, a water-tested cycle, a check valve with a clear vent hole, and an open line out. That's the whole inspection, in the order a service tech would work through it.
Run it now, then repeat the water test monthly through the wet season. Write down the date and whether it started and stopped. A pump that was fine in September and hesitates in December has told you something.
The homes that flood usually aren't the ones with old pumps. They're the ones where nobody tested the pump between seasons. Pairing the test with a smart leak detector covers the hours you aren't home.
Questions about your setup, or want a second set of eyes before the season turns? Call or text us at (604) 897-4989, Monday to Friday, 8:00 AM to 4:00 PM. You can also send us a message for a free quote.
