Wells and How They Work

More than 17 million households in the United States use individual wells to supply water for their families. Wells are used to extract water from aquifers. It takes a lot of energy to get water out of the ground and into cities, homes, and farms.

What is a Well?
Basically, a well is a hole drilled into an aquifer. A pipe and a pump are used to pull water out of the ground, and a screen filters out unwanted particles that could clog the pipe. Wells come in different shapes and sizes, depending on the type of material the well is drilled into and how much water is being pumped out.

Three Basic Types of Wells

• Bored or shallow wells are usually bored into an unconfined water source, generally found at depths of 100 feet or less.
• Consolidated or rock wells are drilled into a formation consisting entirely of a natural rock formation that contains no soil and does not collapse. Their average depth is about 250 feet.
• Unconsolidated or sand wells are drilled into a formation consisting of soil, sand, gravel or clay material that collapses upon itself.

Well Construction
All private well construction is based on establishing the right location for the well, sizing the system correctly and choosing the proper construction techniques. Only a professional water well contractors should install wells. They are familiar with the hydrology in an area and all local codes and regulations. Proper well construction is key to operating and maintaining a well.

A well is composed of many components; the following is a list of the most important materials used:

• Casing is used to maintain an open access in the earth while not allowing any entrance or leakage into the well from the surrounding formations. The most popular materials used for casing are black steel, galvanized steel, PVC pipe and concrete pipe.
• Grout is a sealant that is used to fill in the spaces around the outside of the well. It protects the well against the intrusion of contaminants. A grout mixture can be made of cement, bentonite, or concrete (each used separately).
• Screen keeps sand and gravel out of the well while allowing groundwater and water from formations to enter into the well. Screen is available in many materials, the most popular being stainless steel and slotted PVC pipe. Screen is used when wells are drilled into unconsolidated materials.
• Gravel pack is placed around the outside of the screen to prevent sand from entering the well or clogging the screen and to stabilize the well assembly.

Well Contamination
A well can easily be contaminated if it is not properly constructed or if toxic materials are released into the well. Toxic material spilled or dumped near a well can leach into the aquifer and contaminate the groundwater drawn from that well. Contaminated wells used for drinking water are especially dangerous. Wells can be tested to see what chemicals, pathogens and other contaminants may be in the well and if they are present in dangerous quantities.

Things you can do to protect your groundwater and water well:

• Maintain your well and test the water quality annually.
• Keep household chemicals, paint and motor oil away from your well and dispose of them properly by taking them to a recycling center or household hazardous waste collection site.
• Limit your use of pesticides and fertilizers.
• Install a well cap and keep it clear of leaves, mulch, dirt, snow and other materials.
• Use caution when mowing around your well so you don't damage the well casing.
• Practice water conservation measures in your home and install low water use appliances.
• Learn more about well testing.

About Your Well
For information on your well, contact the well contractor who installed it, or locate a water well contractor in your area by looking in the telephone directory. For more information on drinking water and private wells, visit the US Environmental Protection Agency's website at http://www.epa.gov/safewater/privatewells/booklet/index.html. Learn more about wells at www.watersystemscouncil.org and www.wellowner.org.

If you have specific questions about your well, contact wellcare(R) at http://www.watersystemscouncil.org/wellcare/index.cfm.

Special thanks to the Water Systems Council for contributing information contained in this article.