When drilling a new well, the final well depth depends on upon the geology and underground water levels in your area. Drilling companies use a combination of experience, expertise, and a little educated guesswork to gauge the final well depth. Because the price of drilling is directly related to the depth of the well, it’s important to work with a company with the skills and knowledge of your area to get an accurate estimate before drilling begins.
Aquifers are underground water storage spaces that contain varying amounts of water. Here in New England, water is often found at around 300 feet below the surface, but wells for household use can range from as little as 100 feet to as much as 1000 feet underground.
Basic Well Construction
In New England, our geology is extremely rocky. A bedrock well is one that is most common to our area. This consists of drilling deep into solid rock and tapping into the fissures that carry water. A typical household well is about six inches in diameter and uses a six-inch casing or liner. A casing pipe is then installed down the shaft to the bottom of the well to keep out surface water, sand, and other contaminants. The casing extends about twelve inches above the surface.
Construction typically takes two days with the first day spent drilling and the second day used to install the casing pipe and submersible pump. The location of your well is critical. It’s best to work with a contractor who is familiar with the hydrology and geology of your area. They will not only know the best place to dig but can size the system correctly and will know the codes and regulations for your location. Hydrofracking is sometimes required to get a well to produce at the flow rate needed.
Estimating Well Depth
Generally, the cost of digging a well is based on a price per foot. To get an accurate estimate from your contractor, they should have experience digging in your area and will know the average well depth needed to reach water. As soon as adequate supply is found, drilling can stop. While a water well contractor can’t tell you exactly how deep they’ll need to go to get water, they can make reasonable judgments about water quality and quantity based on previous experience.
Yields can be increased if needed, by fracturing the bedrock immediately surrounding the well shaft. This is done using a technique known as hydrofracking. By pumping large quantities of water deep underground at high pressure, additional fissures in the bedrock are exposed providing access to additional clean water.
The quality of your water depends on several factors including geology and water levels. In order to allow for maximum ground filtration to remove impurities, your well depth should be at least 100 feet. As a general rule, the deeper you drill, it’s more likely that there will be minerals present. Which could require the installation of a water softening unit.
The best way to begin is to get a list of state certified drilling contractors from your local health or water department. Your well professional can advise you as to your options and the costs involved. Your well is the most important asset you own. Work with a qualified contractor to make sure the work is done properly. Your family’s health and well-being depend on it!