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Articles Generators Informational Topics

What Size Generator Do I Need for Well Pump: Inclusive Query Solving Guide

If you live in an area where the water supply to your home is inadequate, a well pump is necessary to fulfill your daily freshwater supply needs.

Having a personal water pump can take no time to deliver fresh water to your household, kicking off the issue of water stoppage or inadequate water supply.

The main query that needs to be solved is what size generator I need for a well pump.

You might be well familiar with a well pump, but for those new onboard, let me give it a touch to make it clearer to you.

A generator for a well pump is an electromechanical module that helps draw out water from the pre-drilled well.

What Size Generator Do I Need for Well Pump

With the help of a well pump, you will get cold water in summer and warm water in winter, eliminating your concerns about weather conditions.

All you need is to turn on the well pump switch, and an endless stream of fresh water will start delivering to your home and farms or the place you installed it.

But wait! What if you are out of electricity? What if your power source is out of work due to any issue, including calamities, transformer issues, electrical wiring issues, and many more?

You might be thinking, what’s next? It’s simple! It would help if you had an alternative power supply (generator) to get your well to work. Things might get more complicated.

Powering A Well Pump Using A Generator:

A well pump is used to pump water from the water table or underground water channels into the storage systems inside a house or for industrial purposes. A well pump is used over the AC power supply but you can also use it with the generator and for that purpose, you would have to make certain changes to the power supply. You need to have the following items for powering your well pump with a generator;

  1. Generator
  2. Transfer switch
  • Proper wiring

Whenever power outages happen, the power supply from the grid or utility line will be shifted to the generator outlets and this job is done by the transfer switch. A transfer switch will overcome the hurdle of manually turning on the generator each time an outage happens.

To ensure the safe and risk-free use of a generator, it is necessary to be ground, and therefore, it should have proper wiring to avoid electrocution.

Different Types Of Well Pumps

There are different types and sizes of good pumps available on the market and these sizes and types determine the average wattage of a motor that will be used for running this powerful well ump. The common types of good pumps used for various applications including both residential and industrial are enlisted below:

Submersible Pump

Submersible pumps are installed within the wells under the water level and the usual depth for installing these types of pumps is about three inches in diameter below the water level. The type of motor used in the well pumps is typically 2 to 3 ft. along with an average diameter of 3.5 inches.

Jet Pump

These pumps are used where the 3.5 inches diameter is not required and are installed either on top of the well or on side of it. These types of pumps are the most common items in households. And are used with the shallow drive point systems to fetch water from the nearby water tables.

Turbine Pump

These are heavy-duty machines that are used for obtaining a large amount of water. The turbine wells are using an impeller that is attached at the bottom and is used for pushing up water. While the top of the turbine pump has a shaft that goes inside the water.

Cylinder Pump

The cylinder pumps are typical hand pumps and are also used in windmills. These pumps use a rod to pull water from underground water tables. The cylinder pumps are almost eradicated due to the facilities of jet pumps and submersible pumps.

What Size Generator Do I Need For a Well Pump?

You will be acquiring a generator to get back your power supply, but what about the generator size for the well pump? Because you might need a different size generator based on your good type, wattage, and size.

We have suggested the standard generator for your standard well pump to keep it running efficiently to solve this query.

After selecting the right well pump, the wattage generator for your well pump will ultimately conclude it is the right size generator for the pump.

Standard Ratings:

A 1 HP submersible pump can run on a 1000-watt generator. Still, it would help if you acquired a 4000- to 5000-watt generator because the generator requires double the power to run your well pump more efficiently.

Some professionals even suggest a 2238 watts generator for a standard 1.5HP pump. 

Factors Affecting Generator Size Selection:

The following are the Factors to be considered before selecting the right-sized generator for your well pump. Your well pump may require a specific power rating to run efficiently.

Check the label for the required power. Find out which power rating your generator requires and compare it to the desired wattage to get the right size generator for your well pump.


  • 230 volts single-phase 
  • 120 volts single-phase 

Watt Vs. Voltage:

A 2000-watt generator provides sufficient power for a single-phase 120 volts, while a 4000-watt generator provides sufficient power for a single-phase 120 and 230 volts.

Wattage Rating:

The generator’s size is determined by the needed generator wattage. After selecting the right wattage generator for your well pump will ultimately conclude it is the right size generator for the pump.

Types Of Fuel:

Choosing the right-sized generator may require checking the fuel type necessary for running your well pump efficiently. We have multiple options, comprising;

  • Gas and Oil 
  • Gasoline
  • Diesel


For multi-functionality, consider a dual-mode generator for ease and efficiency. 

Consequences Of Sudden Voltage Change-All You Need To Know:

An active power source plays a key role in keeping a constant fresh water supply, and without electricity, you may suffer from a shortage of water.

A sudden voltage change in the power supply might adversely affect your pump efficiency and make you in a mess-up situation.

Even if the power supply gets back to normal, it might damage your pump and make it unable to work.

To avoid such inconveniences, keep an alternative active source to cover the power supply shortage to keep your well pump running effectively and efficiently.

How To Calculate The Generator Required Wattage To Select The Right Size Generator?

For a standard 1.5 HP well pump; (Generator size for 1.5 hp well pump)

1.5 HP x 746 = 1119 watt 

Multiply your answer by 2

1119 watt x 2 (double power) = 2238 watt

You require 1119 watts for starting the well pump, while to make your pump run efficiently, you will need to double the power, 2238 watts for running a standard 1.5 HP will pump which makes Champion 2500 the ideal generator.

You can calculate using the same procedure to select the right size generator for your well pump and solve your query of What Size Generator Do I Need for Well Pump?

Can You Run The Well Pump Without Electricity? 

You might be thinking, can you run the generator without electricity?

The answer is no. The well pump generator comprises hard-wired settings to your home’s circuits requiring electricity for running.

Therefore, your unsuccessful attempt to change the connection could leave you in a hazardous situation. Avoid making such decisions without contacting experts.

Keep your power supply active to get fresh water delivery without any inconveniences.


1.   Can A Generator Damage A Well Pump?

Yes, a generator can damage the well pump and the common problem the well pump running on the generator supply will face is overheating. The overheating of the well pump is most typical with high-wattage generators. That is to say that if your generator has a massive wattage and is supplying high power input to the well pump, it will lead to overheating and may also cause it to break. On the very contrary, if you end up using a limited-wattage generator, the well pump may not have sufficient power and therefore, the water will not flow through the pipes.

2.   How Much Does It Cost To Run A Well Pump Monthly?

The exact cost of running a well pump depends on the horsepower of the pump and thus indirectly on the amount of electric power supply or kilowatts per hour (billing units) used in running the [pump. For instance, a normal ½ HP to 2 HP well pump that is common in households will be using somewhere between 70 to 80 USD per month. On the other hand, if someone is using a massive heavy-duty 5 HP well pump which is the case with a big pump for irrigation, the running cost will be doubled with an average of 150 USD.

3.   Why Isn’t My Well Pump Working?

A malfunctioning or out-of-order well pump can be a really annoying deal as, without it, you won’t be getting any water in your water storage tanks. The major reason why the well pump can stop working is the lack of power, therefore, if your pump is not working be sure to give a heads-up to your power supply and connection cables. If there is no fault with the supply line, then tripped breakers could be the culprit here. Among other causes of a well pump not working, the damaged or leaking pipes can be a problem, or your water tank system may have a faulty pressure switch. If the well pump is malfunctioning then an issue with the relay switch can be a possible factor and it needs to be replaced for restoring the pump functioning.


After getting through this summarized guide, most of your queries about what size generator I need for a well pump should be clarified. You might be able to select the right-sized generator for your well pump by keeping the prime factors in consideration. Having your well pump with the right generator eliminates all water shortage inconveniences during unfavorable circumstances. Proper maintenance of your well pump and generator keeps a continuous freshwater supply to your household and farm.

Thanks for staying till the end. Have a good day!

Related Articles:

What Size Generator Do I Need For The Sump Pump
What Size Generator Do I Need For Power Tools

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About the author

Anthony Miller

Hello Guys! I am Anthony Miller, a high dynamo, communicative author, and editor of the Renewable Cop, always providing amazing, engaging, informative, unique, highly researched, and verified content based on all sorts of generators. Read more.

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