Sump pump emergency
The pump has stopped and the pit is filling. This is the first-hour playbook: stay safe, work out how much time you actually have, and pick a stopgap that can keep up with the water coming in.
Right now
Stay out of the water. Call an electrician for power you cannot shut off from a dry spot, and your gas utility or 911 for a gas smell.
Short answer
If your sump pump fails and water is rising, stay out of any water near outlets or cords. Check the plug, GFCI and breaker from dry ground, then time how fast the pit rises: that tells you how long you have and how big a stopgap you need. Pump water at least 10–20 feet from the foundation, and replace the pump before the next storm.
Most advice for this moment is a list — cut the power, grab a wet vac, call someone. The list is not wrong, but it has no numbers and no order, and a wet/dry vacuum cannot keep up with a storm. The sections below give you both.
First 10 minutes
If the pump is
Likely: No power reaching the pump, a stuck float, or a burned-out switch or motor.
Do now: From dry floor: check the plug (including a piggyback float plug), the GFCI and the breaker. Unplug before freeing a float.
Why a sump pump stops workingIf the pump is
Likely: A jammed impeller, a stuck check valve, an air lock, or a frozen or blocked discharge line.
Do now: Unplug it — a pump running against a blockage overheats. Start a stopgap, then check the valve and the outlet outside.
Check valve problemsIf the pump is
Likely: The pump is working but inflow is beating it, or the discharge is partly restricted.
Do now: Leave it running. Add a second pump alongside it, and time the rise so you know the gap.
Size a pump for measured inflowIf the pump is
Likely: The pump is fine; it has nothing to run on. The most common storm failure.
Do now: Generator outdoors or a power station with enough surge. Meanwhile, lower the pit by hand and lift belongings.
If the power is outTime left
Measure how far the pit rises in one minute. Because a pit is narrow and a floor is wide, the answer comes in two parts: when the pit spills, and how long after that the floor fills.
Measure across the top of the pit if unsure.
Mark the water level on the pit wall, wait, then measure how far it rose.
60 seconds is easiest. Use 30 if it is rising very fast.
From the water surface up to the basin rim or floor. Enter 0 if it is already spilling.
The open floor the water would spread over. Low spots flood first.
Water coming in
6.6 GPM
6 in/min · 1.1 gal per inch of pit
Pit overflows in
about 2 minutes
at the current rate
Then 1" on the floor
about 1.6 hours
averaged over the floor
A working 1/3 HP pump would run about 19% of the time at this inflow. On a 1,000 Wh portable power station (about 800 W running) that is roughly 5.6 hours, if the station can also supply the motor's starting surge.
Planning estimate only. Inflow changes as rain intensity changes, basements are rarely level, and stopgap flows are typical ranges rather than ratings for any product. Re-measure every 15–30 minutes.
The reference table uses a pit with 15 inches between the water and the rim and a 1,000 sq ft floor. At 10 gallons a minute — a steady rain feeding a perimeter drain — an 18-inch pit rises about 9 inches a minute and spills in under two minutes, but it takes about an hour for water to average an inch across the floor. Basements are rarely level, so the low corner gets wet sooner.
| Inflow | Rise in an 18" pit | 18" pit spills in | 24" pit spills in | Then 1" on a 1,000 sq ft floor |
|---|---|---|---|---|
| 2 GPM | 1.8 in/min | 8 min | 15 min | 5.2 h |
| 5 GPM | 4.5 in/min | 3 min | 6 min | 2.1 h |
| 10 GPM | 9.1 in/min | 2 min | 3 min | 62 min |
| 20 GPM | 18.2 in/min | < 1 min | 1 min | 31 min |
Planning figures: 18-inch pit ≈ 1.1 gal per inch, 24-inch pit ≈ 2.0 gal per inch, 1 inch over 1,000 sq ft ≈ 623 gal. Inflow changes with rain intensity, so re-measure.
Stopgaps
Compare your measured inflow with what each option realistically moves out of a basement, not the number on the box.
| Stopgap | Realistic flow | What it needs | The catch |
|---|---|---|---|
| Buckets (5-gallon, carried out) | ~1–3 GPM | Two or more people, a clear path to a door | A 5-gallon bucket filled to the top weighs over 40 lb; most people manage half-full loads up stairs, and pace drops within minutes. |
| Wet/dry vacuum (12–16 gal) | ~1–2 GPM | A GFCI-protected outlet reached from dry floor | A full 12-gallon tank is about 100 lb of water. Empty it at a third to half full, which is where most of the time goes. |
| Utility / transfer pump (1/6–1/4 HP) with garden hose | ~5–12 GPM | GFCI outlet, garden hose run outside | Box ratings of 20–30 GPM are at zero lift and short hose. A long 5/8" garden hose up out of a basement cuts that sharply. |
| Spare submersible sump pump (1/3 HP) with 1½" lay-flat hose | ~25–35 GPM | GFCI outlet, lay-flat or discharge hose clamped on, a route outside | The best stopgap by far — the same class of pump that failed. Rated around 34 GPM at 10 ft of lift; far less through a garden-hose adapter. |
| Gas trash pump (2") — outdoors only | ~60–150 GPM | Engine stays outside; suction hose run in through a door or window | Carbon monoxide: never run it in the basement, garage or near an opening. Suction lift is limited to roughly 20–25 ft, and it is for deep standing water, not a pit. |
A wet/dry vacuum is on every emergency list, but it only holds a slow leak: the limit is how often someone can carry a heavy tank outside. If the pit is rising more than about 2 inches a minute in an 18-inch basin, go straight to a pump. A spare 1/3 HP sump pump with a lay-flat hose is the stopgap that matches a storm, which is why keeping one on a shelf is the cheapest insurance on this page.
Power out
A pump with no power is the most common storm failure, and the one a backup is bought for. Here is what it takes to run it.
| Pump size | Running watts | Starting watts |
|---|---|---|
| 1/4 HP | 500–600 W | 1,000–1,300 W |
| 1/3 HP | 700–900 W | 1,300–1,800 W |
| 1/2 HP | 900–1,100 W | 2,000–2,200 W |
| 3/4 HP | 1,100–1,500 W | 2,600–3,000 W |
Planning figures from published generator wattage guides. The pump's nameplate governs; motors vary by brand and age.
The time-left calculator above estimates that duty cycle from your measured inflow. For the next storm, a battery or water-powered backup pump installed in the same pit handles this automatically; see battery and water-powered backup options.
Get help
| Situation | Who usually handles it |
|---|---|
| Pump is dead but the water is under control | A plumber or waterproofing company for a replacement pump, ideally with a check valve and alarm reviewed at the same visit. |
| Water is near electrical equipment or the panel | An electrician, or the utility to cut service. Stay out of the water. |
| Water has reached drywall, carpet, insulation or finished floors | A water damage restoration company for extraction and drying. Materials that stay wet for 24–48 hours are a mold risk. |
| Sewage smell or dark water | Restoration specialists. Treat it as contaminated; avoid contact. |
| The pump works but cannot keep up, or this keeps happening | A waterproofing assessment of inflow, pump capacity and discharge once the water is gone. |
If the water came from somewhere other than the pit — a wall, a window well, a floor drain backing up — the cause is different; see other reasons basements flood.
Insurance
Standard homeowners policies often exclude water that overflows from a sump pit or backs up through a drain. Coverage usually comes from a separate water backup or sump overflow endorsement, which carries its own limit. Before you clean up, photograph the pit, the pump, the float, the water line on the walls and anything damaged. This is general information, not coverage advice — your policy wording decides.
Afterwards
Work through what to do after the water stops for documentation, cleanup and drying. Then find out why the sump pump stopped working before replacing it like for like, and test the new pump before the next storm.
Related pages
Diagnose the fault once the water is under control.
Read nextDocumentation, cleanup and drying.
Read nextIf the pump runs in winter but nothing leaves the pipe.
Read nextReplacement, alarms and battery or water-powered backup.
Read nextFAQs
Not necessarily, and not instantly. It depends on how fast water is entering the pit. In dry weather a pit may take days to fill; in a heavy storm an 18-inch pit can reach its rim in a few minutes. Once it spills, water spreads across the slab, and an inch over a 1,000 sq ft floor is about 620 gallons, so the floor fills far more slowly than the pit. Time how far the water rises in one minute to know which situation you are in.
Yes. Buckets or a wet/dry vacuum can lower a pit, but realistically they move only 1 to 3 gallons a minute once you account for carrying the water out. That holds a slow trickle, not storm inflow. If the pit rises more than a couple of inches a minute in an 18-inch basin, you need a pump: a spare submersible sump pump on a GFCI outlet with a hose run outside is the most effective stopgap.
Only as long as it takes the pit to fill from the pump's switch-on level to the rim at the current inflow. That can be days in dry weather or minutes in a storm. Measure the rise in one minute; the pit holds about 1.1 gallons per inch in an 18-inch basin and about 2 gallons per inch in a 24-inch basin.
Run it from a generator placed outdoors, well away from doors, windows and vents, or from a portable power station that can supply the motor's starting surge. A 1/3 HP pump typically needs about 700 to 900 running watts and 1,300 to 1,800 watts to start. Never run a generator or gas pump inside the house, basement or garage. If neither is available, lower the pit by hand and move valuables up while you arrange help.
Often not under a standard policy. Water that overflows from a sump pit is usually covered only if the policy has a water backup or sump overflow endorsement, which typically carries its own limit. Check your own policy and talk to your insurer. Either way, photograph the pit, the pump and the water level before cleanup.
Only if you can reach the pit from dry floor, the pump is unplugged, and power to that area is safely under control. Swapping a like-for-like plug-in pump is a common DIY job in dry conditions. If water is around outlets, cords or the panel, do not go in: run a stopgap only where it is safe and call a plumber or electrician.
Sources
Flow and wattage figures are planning ranges drawn from manufacturer data and published generator guides, not ratings for a specific product.