How deep should a water well be drilled?

13 Apr.,2024

 

Sourcing water directly from a well has been a common practice for many centuries. Even today, it remains a reliable water supply option for many households, especially those located in rural areas.

But, if you want to draw water from a well, how deep should your well be? The average well depth is about 100 feet underground, but the depth at which you will find potable water will depend on the depth of the water table, the geology in your area, and how much water you consume regularly.

Learn more about well depth before drilling begins, and make sure you follow all local rules and regulations.

Why the Depth of Your Drinking Water Well Matters

The depth of a drinking water well is a critical factor for several reasons. It directly influences both the quantity and quality of the water you draw from the well, so it’s crucial to get your depth right.

Water Quantity

When it comes to the water supply, the depth of your well directly impacts the amount of accessible water. Shallow wells, also known as dug or bored wells, typically reach depths of up to 50 feet. They rely on water close to the ground surface and are dependent on rainfall and groundwater recharge. The limited depth means these wells can quickly run dry during periods of drought or heavy usage.

Deep wells, on the other hand, tap into aquifers, which are underground layers of porous rock saturated with water. These wells can reach depths of several hundred feet and provide a more reliable water supply, as aquifers are less likely to run dry during dry spells. As a result, a deeper well generally ensures a more consistent water supply.

Water Quality

The depth of your well also significantly influences the quality of your drinking water. Water near the surface is more susceptible to contamination from various sources, such as agricultural runoff, septic tanks, or surface water intrusion. These contaminants can include bacteria, viruses, nitrates, heavy metals, and pesticides, posing risks to human health.

In contrast, deeper wells access water that has been naturally filtered through layers of rock and soil. This filtration process often results in cleaner, safer water. Deep wells are less likely to be affected by surface contaminants, which could make them a better choice.

How To Determine the Right Depth of Your Drinking Water Well

You must consider several factors when trying to decide the right depth of your drinking water well. The intricate dynamics between local geology, groundwater levels, and water demand will influence the final depth of your well. What do you need to know, and how deep should a well be?

Local Geology and the Maximum Ground Filtration

The local geology sets the stage for all water well drilling operations. The type of soil, the depth and composition of bedrock, and the location of water-bearing formations known as aquifers, all play significant roles in determining the depth of a well.

In some regions, abundant groundwater resources may be present in shallow sand and gravel aquifers, requiring only a modest well depth. Other areas may only have water available in deep, bedrock aquifers, necessitating a more substantial drilling operation. Furthermore, the quality of the water can also depend on the geological formations it passes through. For instance, water in limestone aquifers may have a higher mineral content, contributing to water hardness.

The Water Table: Groundwater Levels

The level of groundwater, or the water table, is another crucial determinant of your well’s depth. It represents the uppermost level at which the soil or rocks are fully saturated with water. The water table can fluctuate due to several factors, including seasonal variations, rainfall, and human activity.

In regions where the water table is near the surface, a shallower well might suffice. However, in dry regions or during periods of drought, the water table may drop significantly, requiring a well to be dug deeper to access a reliable water supply. Furthermore, the over-reliance on groundwater for agricultural irrigation or industrial use can lower the water table, so you might need to dig a bit deeper.

Water Demand

Finally, the amount of water your household or property needs is a significant factor in determining well depth. A single-family household may require only a modest amount of water, suitable for a shallow well. In contrast, a large family or a property with extensive water needs, such as for irrigation, livestock watering, or an in-ground pool, may require a deeper well tapping into a larger, more reliable aquifer.

It’s essential to consider not just your current water demand but also how much water you might need in the future. For instance, if you plan to expand your family, cultivate crops, or add livestock in the future, planning for these needs can help ensure your well will continue to provide an adequate water supply.

Avoid Poor Water Quality: How To Protect, Preserve, and Maintain Your Well

Maintaining a safe and functional water well extends beyond the initial drilling process. The ongoing protection, preservation, and maintenance of your well require a large strategy. By implementing a comprehensive plan that includes regular testing, correct construction and sealing, and strategic placement, you can help ensure the long-term safety and reliability of your water supply.

Regular Testing

One of the most important steps in well maintenance is regular water testing. The quality of well water can change over time due to a variety of factors, such as changes in the local groundwater system, land use activities nearby, or deterioration of the well infrastructure.

Testing your well water annually for harmful bacteria, nitrates, and any local contaminants is crucial. Additionally, you should also test your water anytime there is a change in taste, odor, or appearance, or if your well system undergoes any major repair.

Regular water testing can help identify any harmful contaminants, such as heavy metals, bacteria, or pesticides, that can pose a threat to your health. If these contaminants are found, more testing may be necessary to determine the source of contamination and appropriate remediation strategies.

Proper Construction and Sealing

A well should be constructed and sealed properly to prevent surface water, which may contain contaminants, from entering the well. This includes using approved well casing materials, ensuring the well cap is secure, and that the wellhead is at least one foot above ground level. The space around the casing should be sealed with grout to prevent surface water and potential contaminants from seeping down along the casing into the aquifer.

Furthermore, an aging well can become an avenue for contamination if not properly maintained. Periodic inspection by a qualified professional can help identify any structural issues, such as cracks in the casing, a damaged well cap, or signs of corrosion, that could compromise the integrity of the well.

Safe Distance from Potential Contaminants

The location of your well in relation to potential sources of contamination is another crucial factor in preserving the quality of your well water. It is important to ensure that your well is situated a safe distance away from potential contamination sources like septic tanks, chemical storage, livestock areas, and fertilized fields.

Adhering to recommended minimum separation distances can significantly reduce the risk of harmful substances seeping into your well. While specific guidelines can vary based on local regulations, a general rule is to maintain a distance of at least 50 feet from septic tanks and 100 feet from petroleum tanks, fertilized fields, and livestock yards.

Invest in the Best Products for Your Well Water From DROP

Ensuring the safety and quality of your well water doesn’t stop at digging the right depth. It extends to ongoing water treatment and protection measures. At DROP, we have a wide selection of products available, including our pump controller!

The DROP Pump Controller will monitor your water usage and pump diagnostics, giving you the information you need to protect your well and water supply. Take a closer look at our products today, and take control of your water supply.

If you are getting ready to have a water well drilled, you may have questions about the depth of the well. What depth is required to get a well that functions correctly, providing the quantity and quality of water you need? Well drilling needs to be done by professional experts who have experience because the answer to this question is “it depends.” The water well contractor cannot tell you exactly how deep to go to get water or even predict the exact quality of the water that will be tapped. However, a skilled contractor can make reasonable judgments based on previous experience. So, you get more accurate predictions from a well-drilling company the more experience they have.

A well drilling company like A&T Well and Pump uses expertise, experience, and education to accurately determine how deep your well should be. Because the depth of the well can affect the price, it’s important to find a company with the skills to give you an accurate estimate before drilling begins. A&T Well and Pump has the experience you need from which to accurately predict the depth to drill your well. In this article, we explain several factors that contribute to how deep your water well should be drilled.

Typical Depth of a Water Well

The typical depth of a residential well ranges from 100 feet to 800 feet deep. Some wells are even 1,000 feet or deeper. The deeper a well is, the better the water quality. The average well depth in your location depends on several factors: 

  • Geology
  • Water Quality and Quantity
  • Water Table
  • Risk of Contaminants

Construction of a Basic Well

A typical household well is about six inches in diameter and uses a six-inch casing or liner, which extends about 12 inches above the surface. Then, a casing pipe is installed down the shaft to the bottom of the well to keep out surface water, sand, and other contaminants. 

Well construction usually takes about two days to complete. The first day is spent drilling and the second day is the casing pipe and submersible pump installation.

The Geology of Your Property

The quality and quantity of water from your well depends upon the geology and hydrology of the land in which it lies. Well water comes from underground aquifers that exist throughout the ground at different depths. An aquifer is a pocket of water within the bedrock. A well drilling contractor uses science and educated presumption in determining how deep to drill in order to gain access to a sufficient supply of water in the aquifers.

The location of your well is crucial in providing high quality and sufficient quantity of water. It’s best to work with a well drilling contractor like A&T who knows the hydrology and geology of your area. They will know the best place to dig and also how to size the system correctly. A local contractor will also know the codes and regulations for your location.

Water Quantity and Quality

Generally, the quality of your well water improves the deeper the drilling goes because minerals become richer. Over the course of the year, the water table rises and falls depending on the amount of rain and how the groundwater supply is being used. Therefore, the depth of the well needs to be such that it accommodates the times of the year when the water table is at its lowest level. An experienced and knowledgeable contractor will know about the water levels and climate conditions in your area. 

Yields can be increased, if needed, by fracturing the bedrock surrounding the well shaft. This process is known as hydrofracking. By pumping large quantities of water deep underground using high pressure, additional fissures in the bedrock are exposed providing access to additional clean water.

Risk of Contaminants

Wells are equipped with components that filter out debris and prevent bacterial contamination so you have healthy, clean water for you and your family. However, wells can still get contaminated. The deeper your well is, the lower the risk of contamination. Any bacteria that get into the well have a longer way to travel into your home and are more likely to die or get trapped along the way.

Contact Us to Drill Your Well

A&T Well and Pump are experts in drilling wells. Our experience and knowledge enable us to provide you with educated determinations for the depth of your well. Call us at (919) 291-4063 or complete the form below to get a quote from our licensed water well pump professionals.

How deep should a water well be drilled?

How Deep Should a Water Well be Drilled?