Drinking Water Well Components

It's a good idea to familiarize yourself with your well system, since this is the source of your drinking water.

Typical well system components

Casing: The casing is a tube in the ground that houses the well pump and the pipe that moves water from the pump to the surface. It also prevents the hole from collapsing, and keeps contaminants from entering the water supply. Modern well casings are typically 5" plastic (PVC) pipe.

Cap: The cap is the top of the well casing. The cap usually has a screened vent to prevent insects from entering the well. The cap also keeps rainwater and small animals from getting into the well.

Pump: The well pump draws water up the hole and pushes it into the home. The well pump is usually submersible. This means the pump is installed in the well casing several feet below ground, making it operate more quietly.

Pressure Tank: The pressure tank is usually a 3-4 foot tall cylinder located in the home. It stores water and distributes it through the home at an even pressure. The tank can also serve as additional storage for low-yield wells. The pressure switch located at the tank controls the pumps on/off cycle.

Pitless Adapter: The pitless adapter is a plumbing fitting that attaches to the well casing and routes the water supply line from the pump to the home. It is installed approximately 4 below ground so it is not subject to freezing. Before these were invented, old wells often terminated below ground in pits, or basement off-sets. Pits are no longer necessary, hence the name pitless adapter.

Screen: The screen is at the very bottom of the well, attached to the casing. It keeps sand and gravel out of the well while allowing groundwater to flow into the well. Some wells drilled into bedrock do not need screens since the water travels through crevices in the rock, and there is no sand to filter out.

Wellhead: The part of the well that is above ground. The cap covers the wellhead. The top of the wellhead should be at least 12 inches above the ground.