I want to purchase a portable generator to run the 2 sump pumps in my house in the event of a power outage. One is in the front of my house and one is in the back. (I do not have a french drain, so they aren't pulling from the same water source.) I do not plan to run anything else.

I'm not sure if the sump pumps are 1/3 or 1/2 HP, but I used an inline amp meter and I know that one pump pulls a continuous draw of 12 amps, while the other pulls a continuous 10 amps.

I'm looking to size out a generator, but I'm having trouble doing so due to the starting amp draw. (I don't know what the draw is, as I didn't install these pumps and I can't find any model numbers on them.)

22 amps yields somewhere around 2600 watts when both are running at the same time. A small, 3000 watt generator would be able to handle that continuous wattage. The startup wattage draw is more confusing to me, because what happens if the two pumps start at the same time? I do not know the odds of that happening and I don't know if the startup draw would pull for 1 second or 1 millisecond. (The shorter the startup time, the less likely that the 2 would overlap.)

During a storm, my pumps will usually run for about 10-15 seconds and then turn off for a few minutes.