Sizing Backup Power for Your Well Pump - A Plain-English Guide for Rural Homes
Last verified: September 2026
How to land on the right generator size for a home on a well — the simple recipe, where the real numbers come from, and why you always confirm the final figures with your well company and a licensed electrician. Rather have a hand? My number is (330) 200-8042.
Sizing a Well-Pump Generator, at a Glance
Sizing a generator for a well pump is really just a short recipe: the running watts of everything you want on at once, plus the single biggest starting surge — usually the pump's — plus a generous cushion of headroom. This guide walks through it in plain English, shows you where the real numbers come from (your pump's nameplate and your well company, never a guess), and is honest about the last step: confirming the final figures with your well company and a licensed electrician before you buy. There is a printable, 29-page version up top.
Common Questions
1 How do I size a generator for my well pump?
Add up the running watts of everything you want on at the same time, add the single biggest starting surge on top — usually the pump's — and finish with a generous cushion of headroom. Then confirm the figure with your well company and a licensed electrician before you buy.
2 Where do I get my pump's real numbers?
From the nameplate on the pump's control box or pressure-tank setup, or by calling the company that drilled or services your well. Never guess — a quick phone call beats a made-up number every time.
3 Do I add up every appliance's starting surge?
No. Add the running watts of everything, then add only the single biggest surge on top. Appliances do not all start at the same instant, so adding every surge together inflates the size needlessly.
4 Why does the well pump decide the generator size?
A well pump is a serious 240-volt motor with a large starting surge, and on a rural must-run list that surge is usually the biggest number by a wide margin. Size around the pump first, and the fridge and lights tuck in underneath.
5 Is a bigger generator always better?
No. A right-sized unit with a sensible cushion is quieter, thriftier with fuel, and easier to live with. Generous headroom is good; gross oversizing just wastes fuel and money.
6 Can a soft starter let me use a smaller generator?
Sometimes. A soft starter, installed by a pro and matched to your pump, can substantially cut the starting surge and may bring the pump within reach of a smaller unit. Ask your well professional — see our guide on the startup surge and soft starters.
Would You Rather I Just Help?
Sizing backup power for a well pump is one of the more involved parts of the whole plan, and I genuinely enjoy helping rural families work through it — your pump's numbers, your must-run list, an honest size, and the right questions for a licensed electrician and your well company. A first visit is a flat $99, with a 30-day come-back-free guarantee.
Would you rather I just do this for you?
No shame in it — plenty of folks would rather hand it off, and that's what I'm here for. I'll come to your home, set it up right, and make sure it's working before I leave. Flat $99 per visit — no jargon, no upsell, and every visit is 30-day come-back-free.
Not a hardware job? I can often fix it remotely for $49 — a secure screen-share, up to 2 hours, that you watch the whole time and can end whenever (included free for $39/mo Support Plan members, and it counts toward the $99 if it turns out I need to come out).