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How to Test a Sump Pump: Step by Step Before the Wet Season

Updated November 1, 2026 · General information, not plumbing or electrical advice

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Steps

1. Look at the outside end. NDSU says the discharge pipe outside should not be plugged and should direct water away from the house. Ann Arbor says to clear debris from the discharge point.
2. Unplug the pump and look in the pit. Ann Arbor says to check for silt or debris that could block the float, clog the impeller or clog the discharge. SDSU says to inspect the intake first.
3. Check the float. It should move freely and not touch the pit walls, the discharge pipe or other objects (Ann Arbor).
4. Plug the pump in directly. Ann Arbor says to confirm it is securely plugged into the outlet. If a GFCI is present, test it with its test button.
5. Dry test if the pit is dry. NDSU says to lift the float for about 10 seconds to see if the pump runs smoothly.
6. Water test. Pour water in until the float starts the pump. Ann Arbor says three to four gallons is usually enough. NDSU says to make sure the pump turns on and off at least twice. SDSU says to repeat the process at least once more.
7. Watch and listen. The pump should turn off when the water drops. Ann Arbor says the pump should not have to run all the time. SDSU says to listen for anything strange.
8. Check the weep hole and pipe. A small stream should spray from the weep hole near the pump. Look at the discharge line for leaks.
9. Test the backup. Unplug the primary pump, add water so the backup runs, then plug the primary back in (Ann Arbor).

What a bad result may mean

• Water rises above the pump before it turns on, or it will not shut off: Ann Arbor says there may be a defective sensor or other problem. Refer to the manufacturer's instructions.
• It never turns on: see sump pump not working.
• Odd sounds: see sump pump making noise.
• It runs again and again: see why a pump runs every 5 minutes.

Ann Arbor says these are general guidelines, to follow manufacturer instructions first, and to contact a professional with questions about a specific issue.

Common questions

How often should I test my sump pump?

Ann Arbor says to check it at least twice a year, preferably before the spring snow melts. NDSU Extension says to check it before the snow starts melting, and notes that after mild winters or drought a pump may not have run for a couple of years.

How much water do I pour in?

Ann Arbor says that if the pit is empty, three to four gallons is usually enough to activate the pump. NDSU says to pour water in at a rate similar to normal inflow until the float starts the pump.

Can I test it dry?

NDSU Extension says that if the sump is dry you can lift the float for about 10 seconds to see if the pump turns on and runs smoothly, and that briefly running a pump dry will not do any damage.

What is the small hole in the discharge pipe?

Ann Arbor calls it a weep hole, 3/16 to 3/8 inch, directly above the pump. It prevents an airlock in the discharge lines. A small stream of water should spray out of it when the pump runs. If it is blocked, unplug the pump and clear it.

How do I test a battery backup?

Ann Arbor says to unplug the primary pump and add water to the pit so the backup runs, then plug the primary cord back in. It also says to check the battery water level covers the cells and that a high water alarm activates when the float is raised or water hits the sensor.

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• Sump pump not working: signs and repair
• Sump pump cost
• Battery vs water-powered backup