How to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump PumpHow to Test Your Sump Pump

How to Test Your Sump Pump — Bothell, Washington

Complete checklist with climate-adjusted recommendations for Bothell, Washington

Overview

Pour water into the pit to verify the pump activates and the discharge line is clear.

DIY FriendlyEasy~20 min

Bothell note: Test before spring thaw — this is when your sump pump works hardest as snowmelt saturates the ground. Check that the outdoor discharge pipe is not blocked by ice. Consider adding a freeze guard on the discharge line that diverts water to an alternate outlet if the main line freezes.

Step-by-Step Guide

Locate and access the sump pit

Find the sump pit in your basement or crawl space — it is typically a plastic or concrete basin 18–24 inches in diameter set into the floor. Remove the cover and inspect the pit for debris, sediment, or standing water. The pump should be sitting upright on the bottom of the pit.

Verify the pump is plugged in

Check that the pump power cord is plugged into a GFCI outlet. Most sump pumps use a piggyback plug setup: the float switch cord plugs into the back of the pump cord, which plugs into the wall. Verify both connections are secure. Press the GFCI 'Test' then 'Reset' buttons to confirm the outlet works.

Pour water into the pit to trigger activation

Slowly pour approximately 5 gallons of water into the pit until the water level reaches the float switch activation point. The pump should turn on automatically within a few seconds, rapidly lower the water level, and then shut off. Time the cycle — a healthy pump should evacuate 5 gallons in under 30 seconds.

Check the discharge line for flow

While the pump is running, go outside and verify water is flowing freely from the discharge pipe. The outlet should be at least 10 feet from the foundation and point downhill away from the house. If flow is weak or absent, check for clogs, frozen sections, or a failed check valve.

Inspect the check valve

The check valve is a one-way valve on the vertical discharge pipe, usually 6–12 inches above the pump. It prevents water from flowing back into the pit after the pump shuts off. If you hear water draining back into the pit after shutoff, the check valve needs replacing ($15–$30 part).

Clean the pit and screen

Remove any gravel, sediment, or debris from the pit bottom. If the pump has an intake screen, pull it off and rinse it under water. Sediment buildup can clog the impeller and cause the pump to overheat or fail. Wipe down the float switch to remove any slimy buildup that could stick it in the off position.

Test the backup system (if installed)

If you have a battery backup sump pump, unplug the primary pump and repeat the water test. The backup should activate on its own. Check the backup battery charge level — most battery backups have an indicator light or alarm. Batteries typically last 3–5 years and should be replaced proactively.

What You'll Need

Tools

- 5-gallon bucket
- Flashlight
- Garden hose (optional, for larger volume test)

Cost Estimates

DIY Cost

Professional Cost

$150–$350 for a plumber to test, service, or replace a check valve; $800–$1,500 for a full pump replacement with battery backup

Safety Tips

Never reach into a sump pit without first unplugging the pump — the float switch could activate and the impeller could injure your hand.
If the sump pit smells like sewage, you may have a cross-connection with the sewer system — call a plumber immediately.
Test the GFCI outlet regularly; a tripped GFCI is the number one reason sump pumps fail during storms.

When to Call a Professional

Call a plumber if the pump runs but does not move water, vibrates excessively, runs continuously without shutting off, or is more than 7–10 years old. Also call a pro if you need a backup system installed or if you smell sewage coming from the pit.

Pro Tip

Plug your sump pump into a WiFi-enabled smart plug ($20–$30) that sends you a notification if power is lost. A sump pump is useless during a power outage unless you have a battery backup — and most basement floods happen during storms that knock out power.

Common Mistakes to Avoid

Never testing the pump until water is flooding the basement during a storm.
Letting the discharge line exit too close to the foundation, causing water to re-enter the pit in an endless cycle.
Failing to clean debris from the pit — gravel and sediment are the leading cause of impeller jams.
Relying on a battery backup without checking the battery charge level regularly.