Will A 5000 Watt Generator Run A Well Pump?

  • By: Umer.A
  • Date: June 8, 2022
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Yes, a 5000-watt generator will run a well pump, but the exact numbers depend upon the starting wattage of your well pump.

If you have a large well pump, you need a generator unit between 5000W to 6500W. For example, a generator unit from 4000W to 5000W is required for a single horsepower submersible standard well pump. However, the running wattage of a well pump might range around 1000W. A 5000W generator can power a 1.5HP well pump.

We will find out more about running a well pump using a 5000-watt generator.

How Many Watts Does It Take to Run a Well Pump?

You’ve to determine your well pump’s starting and running wattage ratings. You can check these numbers on the data plate of your well pump or on the user’s manual that came with it.

But if the wattage is not available, the number will be given in amperage and voltage. So, multiply the amperage numbers with voltage numbers to get wattage ratings.

In most cases, the capacities of well pumps range in terms of their motor horsepower. Therefore, you can find a 1HP horsepower well pump with a starting wattage rating of 4000W and a running wattage rating of 2000W.

A well pump with a 1.5HP motor has a starting wattage rating of 5000W and a running wattage rating of 2500W. There are bigger well pumps available as well that come with a 2HP motor and 3 HP motor.

Their starting wattage rating is much higher than 5000W. It means that a 5000W genny won’t be able to power them up. If you have a 5000W generator, you can use it to power a 1HP or a 1.5HP well pump but not big well pumps.

How To Size a Generator to Your Well Pump?

Most of the well pumps available for home or office come with their motor sizes ranging from 1HP to 3HP. In addition, you can go for 1.5HP and 2.5HP well pumps. All these well pumps come with different starting and running wattage ratings.

You need to make sure your generator is big enough to provide your well pump with enough power to start. All appliances have higher starting wattage ratings and lower running wattage ratings. A 1.5HP well pump has a 5000W starting wattage rating, so using a 5000W genny may not be feasible. You need to go for a more significant generator like a 6000W or a 7000W generator for this type of well pump.

The best option is the 1HP well pump with a running wattage rating of 2000W and a starting wattage rating of 4000W. This is the most suitable choice for running with a 5000W generator because you have some wattage left.

You have to consider the starting wattage rating because it is much higher and doesn’t consider running wattage rating because it is lower. Your genny will have plenty of power left for you to connect other devices and appliances.

What Generator Do Professionals Use for Running Submersible Well Pumps?

You can do nothing if you start a pump with a genny that doesn’t come with enough juice to cater to the motor’s starting wattage rating. However, for a reliable generator, you can use a Honda 6500W portable generator available in 120V and 240V single-phase power.

It has enough juice to run a 3HP single-phase well pump (submersible). So, this unit is easy to start. But it’s a large generator, so most houses might not need it. However, if your area experiences many power outages, this is the right option to consider.

Suitable Location for Your Generator

5000W generators are pretty big, and they can be loud at times as well. These units emit toxic gases and pose fire hazards. You need to place your unit so it becomes quieter.

Make sure that you don’t place it inside a directly connected room to your house. The space where you place your genny needs to be adequately ventilated. It should have provisions to tackle those dangerous exhaust fumes.

You also need to ensure it is not present right next to any combustible surfaces. Your generator must have a properly installed spark arrestor on its exhaust. You need to install it so that there is no room for it to tip over due to any cause.

Plan Your Strategy for Generator Electrical Connection

You have to devise a proper strategy for your general electrical connection because it is a matter of safety for you and your neighbors. Furthermore, you have to install a transfer switch compliant with the national and local electrical codes.

You don’t need to install your generator with a separate circuit breaker because it is unsafe. You can also install a breaker interlock if your local codes allow, which only depends on your local electrical code.

You need to plug the items that require power directly into the outlets powered by your generator. This is much simpler and more cost-effective than going for a transfer switch. But there are some discrepancies with this technique.

You will have to run extension cords, and you can only plug in a few important devices into the generator. So, you will have to plug everything back into the house and put away those extension cords when you are done.

Prioritizing Power Requirements in Case of a Small Generator

If you own a genny that is too small to power everything you need, you need to prioritize everything. For example, running an electric stove will not work unless you run them on full low settings.

You will also have to plug your fridge for 8 hours, then plug it out, plug your freezer for eight hours, and then plug it out. And this needs to be done on a rotational basis.

When you are not using those lights, then you will have to turn them off as well. And only use LED lights. But you can keep your computers, mobiles, and internet routers online because they don’t consume too much power.

How many watts does a 1.5 HP well pump use?

A 1.5HP well pump requires 5000 starting watts and 2500 running watts. A 1HP well pump needs 4000 starting watts and 2000 running watts.

What size generator do I need for a 30 amp well pump?

If it’s a 120V well pump, then you will need a 4000W or a 5000W generator to run this well pump. If it’s a 240V well pump, you will need an 8000W or a 10000W generator to power it up.


It’s safe to power a well pump with a 5000W generator easily. But you have to make sure to determine your well pump’s starting wattage rating and running wattage rating.

A 1HP well pump comes with a starting wattage rating of 4000W and a running wattage rating of 2000W, and a 5000W generator is an ideal option to pour it up in case of a power outage. Any other well pump with a bigger motor will need a bigger generator.