How Does Well Water Work? All You Need to Know

By: Jake Gallagher | August 23, 2023

Many new rural home owners have no experience with well water and have no idea how it works. If the idea of well water conjures up images of Laura Ingalls, you probably want to know more about how your water well operates. Well (see what I did there?), you’ve come to the right place!

Nowadays the majority of well water systems have been replaced by modern city water supply lines, but some rural parts of the US still rely on good old wells to provide daily water supply.

Keep reading for the complete details of well water systems and how they work.

What Kind of Well Do You Have?

Knowing the type of water well your property comes with is the first step toward understanding how it works.

Does your well look like this?

Classic dug wells

These are the most basic kind of wells made by digging a hole in the ground with a shovel until it hits the water table underground.

These are shallow wells and go only as deep as 50 ft (15 m). The water is fetched with a bucket and pulley system. Dug wells are most prone to contamination and can be toxic to drink from if not maintained regularly.

Classic wells are quite primitive and, fortunately, not very common in the US. However, many rural areas of developing countries rely on such wells for water systems.

Or this?

Modern bore/drilled wells

Chances are your house has a similar well water system. Such wells are dug with modern rotary drilling machines and use submersible pumps to access groundwater and store it in a pressure tank.

Most common types are bore wells and drill wells. The main difference is the depth and mechanism used to dig holes.

Bore wells are shallower, no more than 100 feet deep. They don’t go beyond the bedrock, instead drawing water from the water table above the bedrock. Due to their shallow depth, they are susceptible to drought and excessive rain. Being closer to the ground also makes them vulnerable to contamination due to surface water. Because of this contamination susceptibility, bore well water needs to be filtered before you can use it for drinking.

Drill wells are much deeper than 100 feet. They are dug using a rotary drill and go beyond the initial bedrock to draw water, making it more reliable, as the water is not affected by drought and rains. However, pumping water from such depth also pumps out minerals like calcium, magnesium, and iron sulfide, which makes the water harder. 

Where Does Underground Water Come From?

It is said that around 15% of the US population draws water for daily usage from their private wells. That makes roughly 42 million people dependent on such resources. If you are one of them, then understanding the science behind it could help you maintain your own private well.

To help you understand how water is pumped from deep underground, here’s a refresher about what actually happens beneath the Earth’s surface.


Groundwater comes from aquifers, which are the pockets of water present beneath the Earth’s surface. The water absorbed in the soil seeps through tiny spaces between the Earth’s molecules, and ends up in a water reservoir beneath. 

Studies show that some of the water molecules present in aquifers are thousands of years old. Check out this basic guide from the National Ground Water Association for more information. 

Water tables

If you start digging, there will come a time when you hit the aquifer underground. The position where you hit the ground and water starts gushing out is known as the “water table.”

Aquifers replenish themselves thanks to nature’s water cycle, but there are instances where excessive pumping out of the water reduces the water table or dries out the aquifer entirely.

How Does a Modern Well Work?

Modern wells work on the same principle as primitive wells do, but the incorporation of high-tech digging processes and the latest machinery make them more efficient and convenient to use.

I have divided the working of modern wells into three parts for better understanding.

Part 1: Digging the hole

Where a hole for a water well is dug is important. This can be a complicated process that involves considerable paperwork. Contacting a licensed well contractor will get you all the information you need for this project.

Once the hole is dug all the way to the aquifer underground, the well will be ready to extract water.

Part 2: Installing water well pump, pipes, and other components

A well casing lines the hole to prevent collapse. It often comes with a pitless adapter that secures the seal from other contaminants. Also, screens are added to prevent sediments and small rocks from damaging the equipment.

A submersible pump is installed, and waterproof electrical wiring is placed. The drilled hole is connected to your water storage tank present in the house through underground pipelines.

The visible part of the well that you see is for repair and maintenance of the well and its machinery.

Part 3: Pumping water into the house

To draw water from a well, the water is pumped from an underground reservoir, stored in the pressure tank, and then supplied to every faucet in the home through a modern plumbing system.

Modern pressure tanks monitor the water levels in the container. Once the water level drops below a certain limit, the pressure switch turns on the submerged water pump, and water is pumped again to an optimum level. You don’t have to worry about anything, as this process is fairly automatic.

Other Components of a Modern Well System

What makes modern wells so convenient is the high-tech machinery that monitors all the processes. Here are some other components that you might need to know about.

Pressure tank

It’s a basic tank that stores the water pumped from underground that you use throughout the day. It’s fitted with a pressure sensor that maintains optimum water pressure in faucets in your home. These sensors also keep track of the water level and activate the pump whenever the water level gets lower in the pressure tank

Water softener

Pressure tanks are often connected to water softeners because the underground aquifers have high mineral concentrations, mostly excessive magnesium and calcium. The presence of these minerals results in hard water

You can do without a water softener, but to improve your water’s taste, protect your pipes and appliances, and keep your clothes and hair soft, you should consider a water softener if you have hard water. For more information, read my article about water softeners.

Filter and treatment plant

Sometimes well water gets contaminated with hydrogen sulfide gas or sulfur bacteria and smells like rotten eggs. Water filters and treatment plants treat such contaminations. People often use reverse osmosis plants, perforated filters, ion exchange filters, and activated charcoal filters.

Usually, water extracted from underground is not safe for drinking water and requires such filters. 

Risks Involved in Well Water


Contamination is the number one concern when it comes to private well usage. It’s not common, but there is a risk of bacteria present in the water. You can avoid it by installing a water filtration plant for drinking water or getting your sample tested.

Some of the most common contaminants found in groundwater are bacteria, viruses, and parasites. Here are a few of the most common:

E. coli

E. coli is a coliform bacteria that affects the digestive system and causes diarrhea, nausea, and fever. It’s not fatal but can cause extreme distress if not treated properly. This sort of bacteria suggests the leakage of sewage or fecal matter into the water streams.

E. coli is most common in wells with a shallower depth. Similar organic toxins include giardia, cryptosporidium, rotavirus, and hepatitis A.


Arsenic is a poisonous natural element and the main constituent of rock and soil underground. It’s also present in industrial waste, which pollutes natural resources.


Sulfur bacteria isn’t very harmful, but it gives off a rotten egg smell that is quite off-putting. Proper maintenance and shock chlorination can prevent these bacteria from growing.


Nitrate is actually quite dangerous, especially to infants. Studies show that nitrate-contaminated water can cause cyanosis (methemoglobinemia), a blood disorder that could be fatal.

So, if you have kids in your home, don’t let them drink well water until it’s properly tested and goes through the filtration plant. You can see more guidelines in the EPA’s private well guide.

Hard water

Unlike city water that is pretreated when it reaches your home, well water may contain excessive calcium and magnesium that make water hard. Hard water irritates the skin, fades clothes, and can cause blockage of pipes due to sediment buildup. 

While drinking hard water isn’t dangerous and in some areas provides minerals to residents who otherwise wouldn’t get it, it’s not always pleasant to drink because of a discernible metallic taste. 

Many homes in rural areas of the US use ion exchange water softeners to treat hard water.

Maintenance of a Private Water Well

1. Keep the opening safe

Make sure the well has a tight seal and rainwater flows away from the opening. Otherwise, rainwater may seep into the well’s opening and pollute the groundwater.

2. Water testing

Yearly testing of your water is enough to detect harmful toxins. According to the Centers for Disease Control and Prevention, you should have your well water tested for pH levels, coliform, nitrates, and lead. If you sense a difference in the smell, taste, or color of your tap water, have it tested by the local health department. Construction in local areas and natural disasters can also affect the quality of groundwater. Contact your local water well contractor for an inspection. 

Cost of a New Well

Sometimes a new well must be drilled because either the well dried up or the groundwater is contaminated.

If you are looking for a new water well, it will cost you around $5,500 for a depth of up to 150 feet. The cost varies, but the price range is between $1400 to $12,000.

How City Water Differs from Well Water Systems

 City waterWell water
TasteNormalSlightly better because it’s fresh water coming from underground
Water billYes, you have to pay the water bill.No. It’s essentially free, but you have to pay construction and maintenance costs for private wells.
MaintenanceMinimum maintenance is required as the city management takes care of everything.You have to keep track of maintenance and contact a local well contractor for expert opinion.
CostApart from the monthly bill, there is no cost. There is also lower risk involved.The initial cost of proper well construction is higher and can go up to $12000.
HealthIt’s safe to drink and use for cooking.It’s safe but most wells need annual testing to detect any contamination.
Effect on property valueNot muchIncreases the property value

Final Thoughts

If you’ve recently purchased a home with a well, don’t worry. You won’t be pulling a bucket up out of the ground. But knowing the inner workings of how a water well works will make you more aware of the well’s maintenance needs. Well water for regular usage is good, and access to your own private water is ideal, but you have to be vigilant when using it for drinking water or cooking. 

Reading this guide is a great first step in understanding how your well works, but make sure you run water tests regularly and have a filtration plant in place.