What is a Well Casing, How to Measure a Well Casing and Well Seals vs Well Caps
Types of Well Casings
PVC Well Casing
Steel Well Casing
A well will either have a PVC or a steel well casing. Older wells will use metal casings, the majority of well drillers now using PVC because it won’t rust over time. Piping may stick a few feet out of the ground, like the above pictures, or just a few inches above ground level. The well casing goes down into the ground and prevents dirt and other debris from mixing with well water.
In softer soils the well casing will go all the way to the bottom of the well. At the bottom of the well there are slotted screens that allow water to flow in through the surrounding gravel pack, which helps provide a filter to keep sand/ debris out.
In areas with bedrock, well casings are drilled down to bedrock, but not cased at the bottom since the bedrock acts as a casing and prevents debris from accumulating.
Well Seal vs Well Cap
Well Caps go over the outside of the pipe. Used in conjunction with pitless adapters in areas that freeze. Pitless adapters connect to piping below ground that has been threaded through a hole drilled in the side if the well below frost line. The well cap has an opening on the side for electrical wires that connect the pump to the controller or breaker box.
A Well Seal slides down onto the well casing, sealing with a rubber ring. It distributes weight from the hanging pump and holds the drop pipe in place. Usually used in warmer environments where hard freezes aren’t expected.
How to Measure Your Well Casing for a Well Seal
Place the end of your measuring tape on the inside of the pipe and measure to the inside of the opposite side, that number will correspond to the correct well seal size. Residential wells commonly have 4,5,6 inch casings.
Older wells or agricultural wells tend to use larger casings, 8,10,12 inch (or bigger diameters) depending on the amount of water needed for pumping.
How to Measure Your Well Casing for a Well Cap
Measure the outside diameter of the well casing. Place your tape measure on the outside lip of the PVC pipe and measure to the opposite outside lip. Place the well cap and screw to tighten down.
Don’t Have Measuring Tape?
Wrap a piece of string around the outside of the well casing, cut it to length and bring the section home. Once you’re back in your shop, take out the tape measure and measure the length of the string to get the circumference of the well. Divide the circumference by 3.14 to calculate the outside diameter of the well casing. Subtract 1/2″ to get your inner diameter.
Length of string in inches / 3.14 = outside diameter of the well casing