What to Do About Rusty Well Casings?
Providing a solid structure made of steel or polyvinyl chloride plastic, well casing supports the walls of your well and protects other components, such as electrical wires, pull cable and water tubing. Well casing installed in older water wells in the United States is made of steel. Over time, steel will rust through and create holes in the casing (corrosion). This allows water and contaminates to seep in from the surface. Rusty well casing can be repaired or, if the well is abandoned, plugged to prevent further contamination of the existing well or contamination of a well nearby.
Types of Wells
Digging wells by hand creates what is known as a “dug well.” In dug wells, the well casing is fieldstone or concrete tiles. Drilled into bedrock, the bedrock well is lined with steel or plastic well casing. Ground water runs through openings in the bedrock and the well casing seals off everything above the bedrock, preventing unwanted materials from entering the ground water. Gravel wells drilled into sand and gravel also use steel or plastic well casing. The well casing extends into the sand and gravel, where a screen prevents particles from contaminating the ground water.
Repairing Well Casing
Installing a new liner or patching an existing liner are two options you can use to repair rusted well casing. In a large well, a complete liner consists of a pump chamber with a liner and a screen at the bottom. The liner is put in place inside the existing well casing and sealed, if necessary. Partial liners are patches to damaged areas of a well casing. Patches can be applied to the surrounding wall of a well casing or to the screen at the bottom. Putting in a new liner or patch may affect the use of the existing pump or the production of the well.
Plugging Abandoned Wells
Remove the well casing or lining and all components that have been placed in the well before you begin. This prevents contamination of ground water due to rusted and corroded components being left in the well. Use a sealing material that is sturdy, waterproof and approved for use in your state. Large wells may require a combination of sealing materials, sand, gravel or rock. After the well is plugged, pack the surface with topsoil so water won’t accumulate on top of the well. Hire a professional to ensure that the well is plugged according to specifications.
Inspect your well every 10 years with a camera. If your well casing is made of steel and you need to replace parts, try not to use different kinds of metals. Using different kinds of metal may lead to rusting in the areas where the metal connects. Wrapping one of the metals in the area they connect may prevent rust. If you use a cleaning solution containing chloride compounds, too much chloride may strip the protective layer off of regular or stainless steel, increasing the risk of rust and corrosion.
- Illinois Association of Groundwater Professionals; Your Water Well System - A System of Choice; Olga Lindsey; 2006
- Roscoe Moss Company: Casing Liners for Large-Diameter Water Wells
- California Ground Water Association; Article 510 –Corrosion Protection; October 2006
- Checklist for Inspecting the Condition of Your Well