How Many Watts Does a Well Pump Use? Running, Starting, and Generator Size by HP

Most home well pumps use about 670 to 2,025 watts while running, depending on horsepower. A common 1 HP submersible pump draws about 1,210 watts at full load. Starting is the hard part: the motor pulls about 4.5 to 6.5 times its running current for a moment, so you need a generator or inverter that can handle that surge.

Below are real numbers from Franklin Electric's submersible motor manual (a major maker of submersible well motors), plus what size generator, battery, or solar setup it takes to run one.

Well pump watts by horsepower

These figures are for standard 4-inch, 230V single-phase submersible motors. "Full load" is normal running. "Max load" is the most the motor is built to draw (its service factor). Check your pump's nameplate or control box for your exact numbers.

Source: Franklin Electric AIM Manual, single-phase motor specifications. A 1/2 HP pump on 115V uses the same 670 watts but pulls 64.4 starting amps.

2-wire or 3-wire? A 2-wire pump has its starting parts inside the motor and no control box. A 3-wire pump has a control box in the house. 3-wire pumps pull less current at startup, so they are easier on a generator.

How much electricity does a well pump use per day?

Less than most people think. The pump only runs when your pressure tank needs refilling.

The USGS estimates each person uses about 80 to 100 gallons of water a day. A family of four using 360 gallons with a 10 GPM pump runs it about 36 minutes a day. For a 1 HP pump:

1,210 W x 0.6 hours = about 0.73 kWh per day.

Watering a garden, filling a stock tank, or irrigation adds more run time, so do the same math with your real gallons.

What size generator do you need to run a well pump?

Most well pumps run on 240V, so the generator needs a 240V outlet (L14-30 or 14-50) and a generator transfer switch or interlock to feed the well circuit. Franklin's minimum generator sizes:

Source: Franklin Electric AIM Manual, Table 5 (externally regulated generators). These sizes cover the pump alone. If the generator also runs your fridge, furnace blower, and lights, add those running watts on top.

In-stock portable generators with a 240V outlet, by the pump they can start:

• DuroMax XP5500HX: 4,500 running watts (gas), L14-30 outlet, CO alert shutoff. Covers a 1 HP 3-wire or 3/4 HP 2-wire pump. $629
• DuroMax XP8500EH: 7,000 running watts (gas), L14-30 outlet. Covers a 1.5 HP 3-wire or 1 HP 2-wire pump with room for a few house loads. $1,075.99
• DuroMax XP13000HX: 10,500 running watts (gas), L14-30 and 14-50 outlets, CO sensor shutdown. Covers a 2 HP pump with about 3,000 watts to spare for other loads. $1,399

For whole-house sizing, see What Size Generator Do You Need to Run a House? and our Generator Transfer Switch Guide.

Can you run a well pump on solar or a battery?

Yes. The daily energy is small. The startup surge is what you have to plan for.

• Energy: 0.73 kWh a day takes about 215 watts of solar at 4.5 sun hours (730 Wh / (4.5 x 0.75)). One 400W panel covers it on paper.
• Surge: a 1 HP 3-wire pump pulls 41.8 starting amps. At 230V that is about 9.6 kVA for a moment (11.2 kVA for a 2-wire). Your inverter needs 240V split-phase output and a surge rating that covers it.
• Storage: if you want water at night or during an outage, the pump runs from your battery backup for home system, so count its daily kWh in your battery sizing.

The easier path is a pump built for solar:

• Grundfos 11 SQF-2 SQFlex runs straight from solar panels on 30 to 300 VDC (or 90 to 240 VAC), with built-in MPPT and dry-run protection, and lifts water up to 395 ft. No inverter needed. $3,099.97
• Grundfos 15 SQ10-250 is a 1 HP, 240V pump with soft-start and dry-run protection, which makes it much easier to start on an inverter or generator. 15 GPM, up to 250 ft. $1,292.04
• Grundfos 10 SQ07-200 is a 3/4 HP, 240V soft-start pump for shallower wells. 10 GPM, up to 200 ft. $1,154.88

See every solar well pump we carry, or size one with our Solar Deep Well Pump Sizing Guide.

Need help sizing? Call 1-888-855-7286. Send us your pump's nameplate (HP, volts, 2-wire or 3-wire) and we will tell you what will run it.

How to find your well pump's exact wattage

1. Look at the label inside the pump control box (3-wire) or the pressure switch area and your well records (2-wire).
2. Find the HP, voltage, and full load amps (FLA).
3. Multiply volts x amps. That gives VA, which runs higher than real watts on a motor. Example: 230V x 8.2 A = about 1,890 VA, while the motor's real draw is about 1,210 watts. For generator sizing, the higher VA number is the safer one.
4. Do not size off the breaker. A 20A breaker tells you the circuit limit, not what the pump uses.

Well pump wattage FAQ

How many watts does a 1 HP well pump use? About 1,210 watts running at full load and up to 1,600 watts at max load, based on Franklin's 4-inch 230V motor data. It pulls about 42 to 49 amps for a moment at startup.

Will a 5,000 watt generator run a well pump? Usually yes for pumps up to 1 HP (3-wire) or 3/4 HP (2-wire), if it has a 240V outlet. Franklin lists 4,000 W minimum for a 1 HP 3-wire pump and 6,000 W for a 1 HP 2-wire.

Can I run a 240V well pump on 120V? No. A 240V pump needs a 240V source. A generator or inverter with only 120V outlets will not run it.

How many solar panels do I need to run a well pump? For a typical household, one or two panels cover the daily energy. The real limit is your inverter's surge rating, or you can use a solar pump like the Grundfos SQFlex that runs directly on panels.

How many amps does a well pump draw? A 1 HP 230V pump draws about 8.2 amps running (up to 10.4 at max load). A 1/2 HP 115V pump draws about 10 amps.

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