How Do Well Pumps Work? Learn How with Heil

Moving into a home with a well can feel like stepping into uncharted territory — especially if you’ve only ever had city water. You might be wondering, “How do well pumps work?” Understanding the basics is easier than you might think and can help save you money and stress down the road.

This guide breaks down how well pumps work, the different types available, and how to choose the right one for your home. Whether you’re troubleshooting issues or just want to understand your system better, this guide is a great place to start.

What Is a Well Pump?

Think of your well pump as the delivery truck for your water system — always on call, ready to pick water up from deep underground and deliver it to your home at a moment’s notice. And after picking up that water, your well pump delivers it to your pressure tank, which acts like a storage warehouse. This tank keeps water pressurized and ready for use whenever you turn on a faucet.

There’s also a pressure switch, which functions like the system’s dispatcher. It monitors the tank and tells the pump when it’s time to make another pick-up and delivery.

Without this team, you’d either run out of water or constantly overwork the pump. Together, they work to ensure your home has a steady, reliable water supply.

Well…How Do Well Pumps Work?

Here’s how your home’s water “delivery system” works behind the scenes:

1. Your pump, which is either located deep in the ground (submersible) or aboveground (jet or centrifugal) draws water from an underground well. This water is pushed or pulled into a pressure tank inside or near your home.
   
2. The pressure tank stores the water and uses compressed air to maintain constant pressure in the tank. As you go about your day — washing clothes, taking showers, running the dishwasher — the water inside the tank gets used, and the internal pressure begins to drop.
   
3. Once the pressure falls to a set low point (commonly around 40 psi), the pressure switch acts like a dispatcher and tells the pump, “Time for more water!”
   
4. The pump kicks on and begins refilling the tank, drawing water back in until the pressure rises to the upper threshold (typically around 60 psi). At that point, the switch tells the pump to shut off.
   

This smart on/off cycle means your pump only runs when needed, preventing wear and tear, saving energy, and ensuring you always have enough water when you turn on the tap.

So how does your pump actually get water out of the ground and into your pressure tank in the first place? That depends on the type of pump your system uses.

The 3 Main Types of Well Pumps and How They Work

Not all well pumps are built the same. The right setup for your home depends on factors like well depth, energy efficiency, maintenance access, and even how much sediment is in your water. Here’s a breakdown of the three main types of well pumps and what each one does best.

How Do Submersible Well Pumps Work​?

Submersible pumps are installed deep inside your well, below the water level. Unlike pumps that sit above ground and try to pull well water up using suction (which only works to about 25 feet), submersible pumps push water up from inside the well using motor-driven impellers. That makes them ideal for deep wells.

Because they’re already submerged in water, they operate efficiently and quietly. They’re also sealed to prevent electrical damage from moisture. One thing to watch for, though: a well that contains a lot of sand or sediment can wear down a pump’s internal seals over time. And if repairs are needed, the whole pump has to be pulled up from the bottom of the well, which can mean a more labor-intensive service call.

How Does a Jet Pump Work​?

Jet pumps sit above ground, either in your basement, utility room, or a nearby well house. They work by sucking water up from the well — kind of like a straw. If your well is less than 25 feet deep, a single-drop jet pump will do the trick. A double-drop jet pump, on the other hand, can handle wells as deep as 110 feet.

Jet pumps are easy to access for maintenance (no digging or fishing them out of a well), but they’re not quite as efficient as submersible pumps at greater depths. Since they don’t sit in the water, they aren’t impacted by sediment. Though maintenance on a jet pump is easier, they do need to be primed before they can run — which means filling the system with water to remove air and create suction. This step is especially important after installation or a power outage, when air can sneak into the lines. For more help, read How To Prime a Well Pump.

How Does a Centrifugal Well Pump Work?

Centrifugal pumps are the most basic type of well pump — and also the most budget-friendly. You’ll find them installed above ground, usually right near the well. They use a spinning impeller (like a fan) to create suction that pulls water up and into your home.

Unlike the other types of pumps, centrifugal pumps only work for very shallow wells (wells that are less than 25 feet deep). They’re a great option if your water table is high and you have a small home or temporary water needs. Just don’t expect centrifugal pumps to work for deeper wells — they simply don’t have the muscle for it. And they do tend to get clogged by sediment or debris in the water, so that is certainly something to consider.

Well Pump Types — Pros, Cons, and Costs

Now that you understand the types of well pumps, it’s time to explore how to determine the correct well pump size.

What Size Well Pump Do I Need?

When it comes to well pumps, size isn’t just about power — it’s about balance. A pump that’s too small will constantly run and wear itself out quickly. A pump that’s too large can waste energy, short-cycle, and cause erratic water pressure. If you’re in the market for a new well pump, choose one that is properly sized to ensure your system is efficient and long-lasting. 

According to our expert well pump technician, Rob, this is the most important factor in ensuring your pump performs reliably and efficiently over the long haul.

So how do you know what size pump you need? It all comes down to your home’s water demand. Each faucet, toilet, shower, and water-using appliance puts a demand on your system.

Here’s a quick way to estimate the correct well pump size for your home:

1. Count up all the fixtures in your home. This includes every sink, tub, shower, toilet, dishwasher, washing machine, and outdoor spigot.
   
2. Multiply that number by 1 gallon per minute (gpm) to find the minimum flow rate your pump should be able to handle.

A typical two-bathroom home might have around 12 total fixtures. According to our formula, that home would need a pump that can deliver 8–12 gpm to comfortably meet demand during peak usage (like mornings or weekends).

It’s also a good idea to consider your future needs. If you’re planning a bathroom remodel or thinking about adding a sprinkler system, make sure your pump is large enough to handle that increased water demand.

Are Well Pumps Expensive to Install and Maintain?

Once you’ve chosen the right well pump, don’t forget to factor in installation costs, which typically range from $1,300 to $5,300 depending on the type of pump, the depth of your well, and how complex the setup is. Submersible pumps tend to cost more to install due to their location deep inside the well, while jet and centrifugal pumps are more accessible and often less labor-intensive.

As for maintenance costs, most homeowners spend an average of $900 over the lifespan of their system. Keeping your pressure switch and tank in good condition can help prevent major issues. Replacing small parts before they fail completely is one of the best ways to extend the life of your pump and avoid expensive repairs down the road.

How Do Well Pumps Work and Other FAQs

Final Thoughts

Well pumps don’t have to be confusing. Whether you’re figuring out a brand-new system or planning a replacement, you’re already ahead of the game just by learning how well pumps work. And if you’re in Howard County, MD or the surrounding area, Heil Plumbing is here to help. Not only can we help correctly size a well pump, we also specialize in Howard County well pump repair and replacement — and we’re always happy to walk you through your options.