PVC is a common plastic pipe material that is popular for water well casing. This pipe is inexpensive, easy to use and durable. You can purchase many of the pipe supplies from either home improvement stores or driller supply companies.
Choose the diameter for your water well pipe. PVC is available in a variety of diameters; however, most residential drinking water and irrigation water wells are two to six inches in diameter. Choose a diameter that is at least two inches larger than the diameter of your submersible pump.
Determine the length of PVC pipe that you need for your well. The total depth of your well will depend on the depth to the water-bearing aquifer. For example, if the top of the water-bearing aquifer is 30 feet below land surface, your well will be at least 35 to 40 feet in total depth to ensure that you have enough screen to produce adequate water flow. If you have not designed a water well before, contact your state's environmental or water department and ask them for information on well depths and design in your area.
Select the type of PVC screen pipe that you will use for your well. A screen is a PVC pipe that has holes to allow the water to flow into the well. There are three common types of screens, including slotted, wire wrapped and louvered. Louvered screens tend to clog easily while wire-wrapped screens have the most open area but are the most expensive. Slotted screens are relatively inexpensive and are sufficient for most wells. The information from the environmental or water bureau will tell you the most common types of materials used in your area. Choose a slot size that will hold 90 per cent of the aquifer soil out of the well based on your soil sieve analysis data. Slot sizes range from 0.006 inches to 0.5 inches.
Purchase the PVC pipe for your water well from a home improvement store or a well drilling supply company. The easiest type to assemble is threaded pipe because you can screw it together. You should purchase a solid well point for the bottom of the well, a slotted screen pipe, solid casing pipe and a well cap. You can buy the PVC supplies in five- to 10-foot lengths, typically. You want enough screen length to allow good water flow. Five to 10 feet of screen is usually sufficient. Once you decide on your screen length, the rest of the length should be solid casing. For example, if your well is going to be 30 feet deep and your screen is 10 feet long, you will need another 20 feet of casing. It is a good idea to order up to five additional feet of casing pipe. You will find it easier to install the well with a short length of casing extending out of the ground. You can cut the pipe to the desired elevation with a saw or pipe cutter following the installation.
Assemble the PVC pipe on the land surface before you begin to install your water well. Threaded PVC will screw together and form a tight seal at the joints. Place the solid well point on the bottom of the slotted screen sections. Place the solid PVC casing sections above the well screen, opposite the well point. Use a well cap on top of the solid casing to keep debris from entering the PVC pipe.
A geotechnical engineer can perform the soil sieve analysis and slot size determination for the PVC screen pipe. A local geologist can help you design the well based on groundwater and soil data for your property, if you are unable to design the well yourself.
Do not use PVC glue or tape when assembling the PVC pipe.