When a new well is drilled, a casing will be inserted into the well and anchored to the top of the bedrock layer. The well casing prevents sediment from flowing into the well, and it also helps the borehole hold its shape — without a well casing, the sediment would cause the well to collapse. There are several materials in use today for well casings, and they all have advantages and disadvantages. To learn how to select the right one for your water well installation, read on for more information about the different types of well casings available.
Well casings made from carbon steel have been a common choice for decades. Carbon steel is very inexpensive, so a well casing that's made from it doesn't cost very much, even when used in deep wells. It's also quite strong, which helps prevent the well casing from collapsing.
The main downside of carbon steel is that it's vulnerable to corrosion. It will rust when exposed to water and will rust faster if the water has a high content of dissolved salts or minerals. Rust from the carbon steel casing will end up in the water you drink and shower with, so it reduces your home's water quality. Rust can eventually eat through the entire well casing, causing sediment to flow into your well water. If the rust spreads further, it can compromise the casing's structural integrity and cause it to collapse.
You can prevent rust from forming on the casing by upgrading to stainless steel, but this is rarely done. Stainless steel is much more expensive than carbon steel, so using a stainless steel casing will increase the cost of installing a well considerably.
Plastic well casings made from PVC are common in modern wells, especially if they're shallow. PVC is fairly strong, and it doesn't corrode like carbon steel. It's also inexpensive, which makes a PVC well casing a good option for homeowners who are trying to save money on well installation costs.
Unfortunately, PVC is weaker than carbon steel, and this can increase the likelihood of your well collapsing. Well collapses usually occur after a drought, as you're more likely to pump out all of the water in your well. When a well is full of water, the water pressure inside the well presses against the casing and helps it to hold up. If you pump the well dry, there's no water pressure inside the well any longer, so hydrostatic pressure from water on the outside of the well casing can push inwards on the casing and cause it to collapse.
If your well casing collapses, your well will be ruined and your well pump will very likely be buried. If you have a PVC well casing, it's important to conserve your water during droughts in order to maintain water pressure inside the well and minimize your risk of collapse.
Fiberglass is a good compromise between PVC and steel. Like PVC, a fiberglass well casing won't corrode. However, it's stronger than PVC, which helps to prevent the well casing from collapsing. It's more expensive than PVC but typically less expensive than stainless steel.
Overall, fiberglass is a great choice for a new water well. One downside is that it might require extra time for permitting to use a fiberglass well casing. They're relatively new, and wells are highly regulated by local governments. You may have to ask for an exception to use a fiberglass well casing, whereas a PVC or steel casing would be automatically approved for your water well installation.
If you're having trouble deciding on the material to use for your water well installation, talk to well drilling contractors in your area. They'll have an idea of how deep your well needs to be in order to access water, which can influence your choice of casing. Deep wells often need a steel or fiberglass casing, since PVC is too weak to withstand large amounts of hydrostatic pressure on the side of the casing. In addition, if you live in a region with hard water or brackish water, you may need to avoid carbon steel due to the risk of rapid corrosion.
For more information about water well installation, contact a company like Eckmayer Inc.