How many watts does a well pump use
While running, a well pump draws 1,000 to 2,000 W. Starting it takes 2,000 to 4,000 W for one second. The smallest portable that can run it has 3,500 W.
Watts for running and starting
| Load | Running | Starting |
|---|---|---|
| Well pump, 1 hp | 1,000 to 2,000 W | 2,000 to 4,000 W |
Source: the Champion wattage chart, dated 04-17-26. Check the nameplate on your own well pump for its exact wattage or amperage. Multiply amps by 120 V. Use 240 V only when the load sits on a two-pole breaker, for example a well pump.
Smallest generator able to start it
A generator must supply 4,000 W for startup and handle 2,000 W without exceeding 80% of its rating. For both jobs, the smallest common portable is 3,500 W. Every other load adds its running watts to that same generator.
A 1 hp well pump along with other loads
| Well pump, 1 hp plus | Running | Peak at a start | Smallest portable |
|---|---|---|---|
| lights, TV and the router | 2,570 W | 4,570 W | 4,000 W |
| a freezer and lights | 2,650 W | 4,650 W | 4,000 W |
| a 1/2 hp sump pump and lights | 3,200 W | 5,200 W | 5,000 W |
| a microwave | 3,200 W | 5,200 W | 5,000 W |
| a window AC, 10,000 BTU | 3,200 W | 5,200 W | 5,000 W |
Running watts add up, and only the largest motor start sits on top. Starting output on a portable runs about 25% above its running rating. The appliance wattage chart lists every load.