How Does A Well Work: A Beginner’s Guide to Private Wells

Living off the land is the old-school American dream. Growing your own food, chopping firewood, and enjoying the simple life is something to aspire to.

But in this vision of self-sufficiency, where does your water come from? You need to know how well water works without the municipal water supply.

Here is the essential guide to the different well designs, components and the advantages and disadvantages of a private water supply. Whether you're moving into a home with a private well or just dreaming about getting away from it all, this guide will give you a better understanding of how well water works.

How Does a Well Work?

A well is a hole drilled or dug into the ground to access groundwater stored in aquifers. It uses pipes and pumps to draw water to the surface, where a filter system removes sediment and contaminants for safe drinking water.

Where Does Well Water Come From?

Well water is sourced from underground aquifers. These aquifers are bodies of permeable rock that store and transmit groundwater. Rainwater seeps through the earth and is stored in these aquifers, which also supply springs, rivers, and lakes. The water in aquifers is replenished by precipitation.

Wells are artificial structures that provide access to aquifers. They enable water to be pumped out of the aquifers and brought to the surface for use.

What's The Ideal Depth for a Drinking Water Well?

A well should be drilled to a minimum depth of 100 feet to access clean water. The depth of drinking water well also depends on the depth of the aquifer. A well must reach the aquifer to access groundwater.

Different designs of wells have different depths. Dug wells can be as shallow as 10 feet deep. However, these are typically remnants from the days when drilling technology prohibitively was expensive.

Deeper wells have fewer contaminants, while shallow wells are more likely to contain pollutants and will require premium well water filtration systems and more frequent testing.

The Different Types of Wells Explained

There are three main types of private wells: drilled wells, driven wells, and dug wells.

The Traditional Dug Wells (Bored)

Dug wells are holes that are dug by hand with shovels or with digging machinery, such as a backhoe. They are typically dug to the depth of the groundwater table, around 10 to 30 feet deep, and have a wider diameter than deeper wells. Since digging below the groundwater table is difficult, dug wells are typically shallower.

After the well is dug, it's lined with a casing made of bricks, tiles, or stone to prevent collapse and contamination. Due to their shallower depth and increased susceptibility to contamination, dug wells are less common and are more likely to be found in older homes built before advances in drilling technology. (1)

The Simple Driven Wells

Driven wells are built by driving pipes into the ground. They aim to tap into groundwater above the bedrock, but they are placed deeper than dug wells, typically between 30 and 50 feet deep. They are most effective in areas with sand and gravel deposits below the surface. (2)

Driven wells can be a cost-effective and reliable source of healthy drinking water in the right geological conditions. However, they should be cased to prevent contamination and should be properly designed to avoid surface water contamination.

The Advanced Drilled Wells

Drilled wells are the deepest kind of well found on residential properties. They can reach depths of hundreds or even thousands of feet, providing access to water that's uncontaminated by surface pollutants.

Drilled wells are constructed using percussion or rotary-drilling machinery that cuts or smashes its way through the earth. They must be continuously cased and have a pump placed close to the bottom to bring water to the surface. (3)

Drilled wells are currently the most popular type of well for residential properties.

Understanding the Components: The Inner Workings of a Well

The components of a well include the well itself, the well casing, well caps, well screens, a pitless adapter, jet pumps, submersible pumps, and a pressure tank.

The Protective Well Casing

Well casing lines the inner walls of the well. It's a tubular structure made from plastic, stainless steel, or carbon steel. It, along with grout, protects the well from excess dirt and undesirable groundwater seeping into the well water through the soil.

The material, weight, and length of the well casing are usually governed by local regulations, as well as being determined by the geology of the area.

The Essential Well Caps

Well caps are used to prevent contaminants from entering the well from above. They are designed to exclude soil, insects, and animals, and to provide safety by preventing people from falling in.

Aluminum and plastic are common materials used in the construction of well caps. They are designed to be vented to maintain the appropriate pressure within the well during pumping.

The Filtering Well Screens

Well screens are located at the bottom of the well and serve as a large initial filter to prevent excessive sediment from entering the drinking water supply.

Well screens are typically made of steel formed into tubes. They come in various designs such as continuous slot, slotted pipe, or perforated pipe. The diameter of a well screen can range from 0.25mm to 4mm.

The Convenient Pitless Adapter

The pitless adapter connects the well casing to the water line that runs into your home. Its purpose is to provide a sanitary and frost-proof seal between the well and your home's plumbing. The pipe that carries water from the well attaches to the pitless adapter below the frost line.

Jet Pumps

Wells require a pump to bring water to the surface. Jet pumps are suitable for shallow wells that are 25 feet deep or less. They are installed above ground and use suction to draw water from the well.

Submersible Pumps

Submersible pumps are commonly used in deeper wells. They are placed inside the casing and powered by an electric line that runs from the surface. For optimal performance, it's recommended to place the submersible pump between 10 and 20 feet from the bottom of the well.

Pressure Tank

The well pressure tank is located above ground and contains a mixture of air and well water. It provides access to drinking water by eliminating the need for the well pump to constantly draw water. The pressure tank generates the water pressure in your home and the pressure in the tank decreases as water is used. At a preset point, the pressure tank turns the well pump on to restore the balance of air and water in the tank and to restore water pressure.

Well Location: Where Should I Place My Well?

When selecting a location for your well, it's important to consider the elevation and drainage of the land. Wells should be placed on elevated patches of land to allow rainwater to drain away naturally and prevent surface pollutants, pathogens, and chemicals from entering the well. Avoid building your well on a steep slope.

It's also important to ensure that the well is appropriately located above the target aquifers to provide a steady water supply. The condition of the local groundwater and geology will determine the materials needed for the well's construction. The well casing and screen are crucial in keeping the well free from impurities.

Keep in mind that local construction regulations may also affect the location and design of your well.

Well Water Advantages and Disadvantages

If you’re building a new house, you’re often faced with the choice: should I connect to the city water supply, or build a private well? Here are the well water pros and cons.

Well Water Advantages

Health Benefits of Clean Well Water

City water is often collected from reservoirs and lakes, while water from private wells is sourced from deep underground. Water from deep aquifers is generally purer than city water and absorbs minerals, such as calcium and magnesium, and micronutrients as it moves through layers of soil and sediment underground.

Better Testing Water

The minerals absorbed by groundwater from the sediment it passes through provide a crisper and cleaner taste than city water. City water often has a chemical chlorine taste due to disinfection.

Lower Utility Bills

While installing a well may require an upfront cost, once it's installed, there are no water bills to pay.

Unlimited Water Access During Droughts

During times of drought, municipalities often put restrictions on how much water you can use. If you have a private water supply, you can use as much water as you need, as long as your well doesn't run dry.

Protection in Natural Disasters

During times of flooding, municipal water supplies can become contaminated by agricultural runoff and industrial waste. Private water supplies, while they should be tested after flooding, are often protected during natural disasters, while city water is often contaminated.

Well Water Disadvantages

The Initial Cost of a Well

Drilling a well can cost between $3,750 to $15,300 on average for a residential property. However, shallower wells and wells with a smaller diameter may be cheaper to install but may have more potential for contamination.

The Dependence on Electricity

Pumping water from a well requires electricity which can increase utility bills. Without a backup generator, there may be a risk of running out of drinking water during a power outage.

The Ongoing Care and Maintenance

While the city is responsible for its own water supply, any contaminants and impurities in your well are your problem. You have to test your well regularly to ensure your water is of a safe drinking standard and that iron or sulfur bacteria aren’t proliferating in your well.

The Hard Water Challenges

While magnesium and calcium are healthy in small doses, their presence makes your water “hard water”. These minerals can build up in your pipes, causing damage to your plumbing and appliances, or drying out your skin when you bathe. Well water is more likely to be hard water because it absorbs the minerals of the soil around it.

If your well has hard water, you need a premium well water softener to protect your home.

Keeping Your Well Water Safe: What Filters Does it Need?

Residential wells can naturally become contaminated by impurities in the surrounding soil, as well as by local human activities such as industry and agriculture. There are a wide range of contaminants to be aware of, including:

  • Microorganisms, such as coliform bacteria like e. Coli.
  • Nitrate and nitrite, which can be dangerous for pregnant women.
  • Heavy metals, such as arsenic, chromium, copper, and lead.
  • Organic chemicals from households, industry, and agriculture.
  • Volatile organic compounds (VOCs)
  • Radionuclides, such as uranium and radium, which can be released from mining.
  • Fluoride
  • Sulfur
  • Manganese
  • Iron
  • Zinc

It's important to be prepared to test and filter appropriately for these contaminants. It's worth noting that wells can become contaminated even if they are constructed to the highest standards. Shallow wells can contain agricultural and industrial chemicals whereas deeper wells can contain fluoride, minerals, iron, and sediment. Iron filters and sediment filters are important additions to residential wells to remove impurities before they enter your home.

Frequently Asked Questions about Well Water

No need to raise your hand. Here are all your well water questions, answered.

Do Wells Run Out Of Water?

Yes, wells can run out of water because of groundwater depletion. This occurs when the water table drops below the depth of the well. Prolonged drought, high water consumption from the well, or a nearby well pumping more water from the ground can cause this to happen.

How Does Water Get Into A Well?

Water is not actively “gotten into” a well. Instead, wells are drilled to reach aquifers which contain and transport groundwater from precipitation.

How Does A Well Replenish Itself?

Wells are replenished through precipitation that's forced into the earth by gravity. Rainwater gradually seeps through the ground at a rate of approximately 10 feet per year. This water eventually reaches the aquifer that the well has tapped into, and is then pumped back to the surface.

How Long Will A Water Well Last?

The lifespan of a well can vary greatly, but on average, it's between 30 to 50 years. Factors that can affect the lifespan include its construction, depth, and natural geological features.

How Often Should You Test Well Water?

Private wells should be tested annually for a broad range of contaminants. Additionally, if you notice any changes in taste, smell, or color, you should run another test for bacteria. If the well is to be used by someone who is pregnant, then a test for nitrates and nitrites should be conducted. (4)

The Final Verdict: Is a Private Well Right for You?

The affordability and accessibility of modern technology has made drilling deep wells a common choice for residential properties seeking a private water supply. This means that modern wells can provide clean and safe drinking water for homes.

When planning to drill a well, it's important to consider factors such as the local landscape and geology, as they will affect the well's depth and diameter. A thorough assessment should be conducted before drilling begins.

It's also important to regularly test the water from your well to ensure it remains pure. Remember that owning a well also means taking responsibility for maintaining the quality of the water it provides.

Eric Phillips

Hi, I’m Eric, a Plumber, Home Repair Expert and Chief Editor behind Dripfina. I first became interested in water purification and water safety when I spent a couple of years traveling the world. I not only learned the importance of keeping my own water fresh and pure (yes, sometimes the hard way…) but I also saw how important water is as a resource worldwide. Read more about me...

Leave a Comment