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How many watts does a Sump Pump (1 HP) use?

Running watts
2,000 W
Starting watts
8,325 W
Startup surge
+6,325 W

A Sump Pump (1 HP) draws 2,000 watts continuously once it's running, but its motor needs a brief surge of up to 8,325 watts to start. A generator has to cover that starting surge, not just the running load, or the motor won't start. 1 HP sump/effluent pumps conventionally step up to 230V. Based on a Goulds WE1012H nameplate (12.5A FLA / 36.2A LRA) — 36.2A × 230V. Far higher than a simple running-watts multiplier suggests.

Running it 2 hours/day costs roughly $20.40/month at the U.S. average residential rate (~$0.17/kWh, early 2026, per the EIA) — real rates vary a lot by state and utility. Use your own rate in the House calculator →

✓ Starting watts here is based on a real published/cited motor nameplate locked-rotor-amp (LRA) rating, not a rough multiplier. See the full LRA reference →

Generators that can run this

Prices as of July 2026 — check the current listing before buying.

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