Question: how much power is needed to run a sump pump?
Answer: The higher the horsepower of the sump pump, the larger the generator you will need. For example, a ⅓ horsepower sump pump will have an average starting wattage of 1300 watts and an average running watts of 800 watts. For ½ horsepower models, you can expect about a 2150 starting wattage and a 1050 running wattage.