A professional contractor can do inspections and tests to see if rehabilitating measures will be successful.
The contractor may start by checking the static water level: The well will often be shut off for 24 to 48 hours to see if the static level – the level of the water table in a well when the pump is not operating – returns to or gets near the original level. If so, rehabilitation will usually work, if other factors suggest success. The contractor will then run a short pumping test to check pump function, flow, water quality, presence of sand, etc.
Before proposing to start rehabilitation, the contractor needs to understand the construction and structural integrity of the well: Is it safe to apply flow, pressure, and mechanical force to the well to clean it? Larger municipal and irrigation wells typically have larger and more robust casings. A well may have been constructed “to the minimum” — have a thin-wall casing, or other deficiencies. The contractor usually starts with the well log or well construction record.
What is the diameter? In many parts of the US southeast, two-inch diameter wells are constructed and attached to jet pumps. These are very difficult to clean with available tools. Even 4 or 5-inch wells, especially if constructed with PVC screens, can be risky to clean mechanically. All these factor into the type of treatment proposed and equipment to bring.
A contractor may recommend (or require) performing a borehole (downhole) video inspection using a slim camera on a reel to observe the well’s structure and condition. There is a cost to this service, but it prevents problems later, and helps the well owner understand the well. The pump is removed for this procedure. At that point, the pump and its operation are inspected. Whatever is clogging the well usually clings to the pump and pipe.
Problems that may prevent or complicate rehabilitation may include debris stuck in the well, casing breaks, changes in diameter or crooked boreholes. The video also shows where to concentrate work, making the process more efficient.