Sump Pump Cost to Run: Calculator + Example Costs
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The short answer: running a sump pump usually costs a few cents to about $15 a month, depending on how much power your pump draws, how often it runs, and your electric rate. The long answer depends on your pump’s amp rating, cycle frequency, your local electric rate, and how long each cycle runs. This page gives you the formula, a working calculator, and worked numbers for three example scenarios.
Running an old, inefficient pump? See our top pick for a reliable replacement: Zoeller M53 →
Interactive Cost Calculator
Printed on the pump’s label or spec sheet. The default is the Zoeller M53’s 9.7 A rating.
Most US residential sump pumps run on 115–120 V.
Time one pump-out.
Divide your bill’s total dollars by total kWh for your all-in rate.
The Formula Behind the Math
Sump pump cost follows one simple equation:
Monthly cost = (Watts × Run hours) / 1000 × Rate per kWh
Run hours is the tricky part. A pump that sounds like it runs constantly during a storm is actually cycling on for 15-30 seconds, then off for 2-10 minutes. Total run time per month is usually much lower than people think — often just 5-20 hours across an entire month of wet weather.
How Many Watts Does a Sump Pump Use?
Horsepower doesn’t convert neatly to electricity use, so start from the amp rating on the pump’s label: watts ≈ amps × volts. Manufacturer ratings for a few pumps we cover:
| Pump | HP | Rated amps | Approx. watts at 115 V |
|---|---|---|---|
| Little Giant BSP33V | 1/3 | 4.4 A | about 505 W |
| Liberty Pumps 257 | 1/3 | 5.2 A | about 600 W |
| Zoeller M53 | 1/3 | 9.7 A | about 1,115 W |
As the table shows, two pumps with the same horsepower can draw very different power, so use your own pump’s label rather than a horsepower rule of thumb. Motors also draw a brief surge at startup; check the manual if you’re sizing a generator.
Three Example Scenarios
Example 1: Dry climate, occasional spring rain
A 1/3 HP pump drawing 5.2 A (about 600 W) runs maybe 2–3 hours a month in the wet season and almost never the rest of the year. At $0.14/kWh, 2.5 hours is 1.5 kWh, or about $0.21 in a peak month — a dollar or two for the whole year.
Example 2: High water table, pump runs most of the year
A pump drawing 9.7 A (about 1,115 W) averages 18 run hours a month. That’s about 20 kWh, or roughly $3.20 a month at $0.16/kWh, with the wettest months running two to three times that.
Example 3: Coastal flood zone, heavy storm season
The same 1,115 W pump runs 50 hours in a stormy month: about 56 kWh, or roughly $10.60 at $0.19/kWh, and a few dollars a month off-season.
How Cycle Frequency Adds Up
The single biggest variable is how often the pump cycles. Short-cycling — where the pump kicks on every 30-60 seconds — is a silent cost leak. A pump that short-cycles 30 times an hour instead of 4 times an hour runs nearly 8x the hours and costs 8x as much to operate, and every extra start adds wear to the motor and switch.
If your pump cycles more than 10 times per hour during rain, check the float switch, the pit size, and the check valve. Our sump pump keeps running guide walks through the four most common causes.
Ways to Reduce Operating Cost
Right-size the pump. A 1 HP pump in a small pit short-cycles more than a 1/3 HP pump matched to actual inflow. For low-volume basements, a budget 1/3 HP pump often costs less to buy and run than a premium oversized pump. See our sizing guide.
Upgrade to a larger pit. A 24×24 pit instead of 18×22 can reduce how often the pump starts, because the pump runs longer but less often per gallon pumped.
Fix the check valve. A failed check valve lets water drain back down the pipe and re-trigger the pump. A bad check valve makes the pump move the same water again and again. Our top picks are reviewed in best sump pump check valves.
Grade the yard. Surface water that ends up at the foundation eventually reaches the pit. Better grading and gutters can noticeably reduce how much water reaches the pit.
Comparing to Whole-Home Electric Use
Even in the heaviest example above, the pump uses about 56 kWh in a peak month. The average US residential customer buys about 899 kWh a month (EIA, 2022), so even then the pump is roughly 6% of a typical bill — small next to HVAC, water heating, or laundry.
Regional Electric Rate Benchmarks
Your monthly cost scales directly with your local rate, and rates vary a lot. EIA’s 2024 average retail prices (all customer types) range from about 8.8¢/kWh in Louisiana and 9.5¢ in Idaho to 27¢ in California and 38¢ in Hawaii (EIA state electricity profiles); residential rates run higher than those averages. The same pump can cost several times more to run in a high-rate state. Pull your most recent bill and divide total dollars by total kWh to get your real all-in rate, including delivery, supply, and taxes.
Time-of-use rates complicate things further. If your utility charges peak rates from 4pm to 9pm and your basement always floods after dinner thunderstorms, you pay more per cycle than someone billed on a flat rate. Homes with rooftop solar and net metering can effectively run the pump for free on sunny-but-wet spring days, though most storms happen when solar output is lowest.
Generator and Battery Backup Cost Considerations
If you run a portable generator during outages, check its runtime rating (hours per tank at a given load) rather than guessing fuel use, and size it from the starting and running watts in your pump’s and refrigerator’s manuals. A pump that only cycles now and then adds little to a generator’s fuel use.
Battery backup math is different again. A 75 Ah, 12 V battery holds about 0.9 kWh in total, and only part of that is usable. How many hours it lasts depends on how often the backup pump cycles — our battery backup runtime calculator estimates it from your own numbers. The bigger ongoing cost is replacing the battery every few years, not the electricity its charger uses.
How to Audit Your Own Pump
The most accurate way to measure real cost is a 30-day plug-in energy meter. Brands like P3 Kill A Watt and Poniie PN1500 retail for $25-$40 and record cumulative kWh. Plug the meter into the outlet, plug the pump into the meter, and leave it alone for a full rainy month. Multiply the recorded kWh by your effective rate and you have a number you can trust.
Related Tools and Guides
If your monthly cost estimate is high, the fix is usually a better-sized pump, a tighter check valve, or a backup setup that doesn’t cycle unnecessarily. Start here:
- See our flagship roundup: Best Sump Pumps of 2026.
- Right-size your pump with the Sump Pump Sizing Calculator or the What Size Sump Pump Do I Need? guide.
- If your pump runs constantly, read Sump Pump Keeps Running? Here’s How to Fix It and How Often Should a Sump Pump Run.
- Stop wasteful backflow with the Best Sump Pump Check Valves.
- Compare the two most efficient 1/3 HP picks: Zoeller M53 vs Wayne CDU980E.
- For backup, see Best Battery Backup Sump Pumps and Battery vs Water-Powered.
Frequently Asked Questions
Does a sump pump use more electricity than a refrigerator?
Usually no. A modern ENERGY STAR refrigerator uses 30-50 kWh per month continuously. A sump pump uses 5-60 kWh per month and only during wet periods. Over a year, the fridge almost always wins by a large margin.
Is it cheaper to run a smaller pump more often?
Not necessarily. Smaller pumps run longer to move the same gallons. What matters is matching pump capacity to inflow so cycles are neither too frequent nor too long. Our sizing guide covers this.
Will a variable-speed sump pump save money?
Variable-speed models are uncommon in residential sump applications. Most cost savings come from correct sizing, larger pits, and reducing water inflow — not from VFD pumps.
How do I measure my actual pump run time?
A Kill-A-Watt meter plugged between the outlet and the pump records total kWh used. Leave it installed for a month of wet weather and you will have a real number instead of an estimate.
Does a backup pump add much to the cost?
A battery backup pump only runs during outages, so its annual electric cost is negligible. The charger that keeps the battery topped up uses about 3-5 watts continuously, which adds roughly $0.40-$0.70 per month.
Are sump pump electricity costs tax-deductible?
For a primary residence, no. For a rental property, yes — sump pump operation is a normal operating expense. Consult your accountant for specifics.
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Photo credit: Hustvedt, Wikimedia Commons, CC BY-SA 3.0.
