Does it start?
Bucket of water in, float rises, pump runs. If you have to jiggle the float, that is the failure, waiting.
The detail
What a properly built sump looks like
A perforated liner below slab level, a pump on a solid base clear of the silt, a float with room to swing, a check valve so lifted water cannot fall back, a sealed lid, and a discharge line that ends well away from the foundation.
Most of the failures we are called to are not dead pumps. They are pits that were too small, pumps sitting straight on silt, floats jammed against the liner, missing check valves, and discharge lines that empty two feet from the wall.
Checklist
Six things to check on the sump you already have
Worth doing in February, before the melt, rather than in April while it is happening.
Does it discharge?
Go outside while it runs. Water at the outlet is the only proof the line is not blocked.
Does it hold?
After it shuts off, listen. Water pouring back into the pit means the check valve has gone.
What is at the bottom?
The pump should sit on a base, not in the sediment that collects in every pit.
Is the outlet buried?
A discharge under a snowbank freezes shut, and the pump runs against a closed pipe.
How old is it?
If you cannot remember installing it, replacing it is cheaper than the flooring.
When it matters
The pump earns its keep in one fortnight
Test it before the melt, not during it. That is the week the water arrives and the week nobody is available.
The limit
When a sump is not the answer
A sump pump moves water that has already arrived. It does not stop water arriving, and installing one because a wall is damp — with no drainage system feeding the pit — achieves nothing except a hole in the floor.
The pit is worth installing when there is, or is about to be, a drain feeding it: an interior drainage system, a replaced weeping tile that cannot run to daylight, or a genuinely high water table. On the sand around Wasaga Beach that last case is common; on the clay south of Collingwood it usually is not.
What a dry lower level is worth protecting
Finished spaceFlooring, drywall and furniture are the expensive part of a basement flood, not the water.
Rooms in daily useA basement office or bedroom cannot be out of service for a fortnight in April.
Before you finish itThe cheapest time to sort the water out is while the room is still empty.
Questions
Questions about sump pumps
How often should a sump pump be replaced?
Treat a residential pump as a wear item rather than a fixture. If yours is older than about seven years, or you cannot remember installing it, test it before the melt rather than during it.
How do I test mine?
Pour a bucket of water into the pit slowly and watch three things: the float rises and starts the pump without sticking, the water level drops quickly, and water actually comes out at the discharge outside. Then listen after it stops — water running back into the pit means the check valve has failed.
Do I need a battery backup?
Ask yourself when your basement fills. If it is during a spring melt on a calm day, mains power will probably be on. If it is during summer storms and wind — which is when Georgian Bay takes the hydro out — then the outage and the water arrive together, and a backup is the only thing that helps.
Where should the discharge go?
Far enough from the house that the water cannot run back into the same backfill and be pumped again. It must not be plumbed into the sanitary sewer, and the outlet needs to stay clear in winter.
Elsewhere