How Many Watts Does a Sump Pump Use?
Sump pumps are critical for basement flood prevention. They run intermittently but need reliable backup power during storms when grid outages are most likely.
Typical Power
500W
Power Range
250-1000W
Startup Surge
1500W
Daily Usage
250Wh
(0.5 hrs/day typical)
Sump Pump Runtime Calculator
Range: 250-1000W
Continuous Runtime
1.6 hours
Days at 0.5hrs/day
3.8 days
Daily Consumption
250Wh
Usable Battery
960Wh
Recommended Equipment
* Calculations assume 85% inverter efficiency and 80% depth of discharge (LiFePO4).
Battery Runtime Examples
| Battery Size | Voltage | Runtime at 500W |
|---|---|---|
| 100Ah | 12V | 2 hours |
| 200Ah | 12V | 4 hours |
| 400Ah | 12V | 8 hours |
* Assumes 85% inverter efficiency and 80% depth of discharge for LiFePO4 batteries.
Sump Pump Power Tips
- •Sump pumps only run 5-10 minutes per cycle, not continuously
- •A battery backup sump pump is essential for storm outages
- •Startup surge is 3x running watts - size inverter for surge, not running watts
- •Test your backup power monthly by unplugging the main pump
- •Consider a 12V DC backup pump that runs directly from batteries
Frequently Asked Questions
How long can a battery run a sump pump?
A 100Ah 12V battery can run a 500W sump pump for about 2 hours of actual pumping. Since pumps cycle, this could cover 12-24 hours of storm drainage.
What size generator for a sump pump?
A 2000W generator handles most sump pumps. The 1500W startup surge of a 500W pump needs headroom, so avoid smaller generators.
What size inverter for a sump pump?
For a 500W sump pump, you need at least a 1500W inverter to handle the startup surge. A 2000W inverter provides reliable margin.