I recently received a phone call from a client we drilled a well for about 6 months ago. He told me the well had water coming out of the top of the well. He said it was creating a lot of water around the well. He asked if this was normal. I told him we would have a technician sent out that day to diagnose the issue.
When our tech arrived on the job, he immediately noticed the water coming out of the top of the well. The house still had water as normal. Thinking that a fitting had failed and was allowing the pump to spray water inside the well he turned the electric off. He then noticed the water flowing out of the well didn't stop. He removed the pump from the well. The well was still flowing and creating a large area of water around the well on the ground. Our clients well was showing characteristics of a flowing Artesian well.
His well is only 60' deep and not confined so it was not a true Artesian well. So what causes a well to start doing this after 6 months of normal use? The aquifer his well was tapped into was now under pressure. It is kind of like a juice box with a straw. If the juice box is just sitting on the table, no juice will come out of the straw. If you squeeze the juice box, juice will come out of the straw. The pressure you put on the juice by squeezing the box pushed the juice to the easiest relief which was the straw.
The water aquifer was now under pressure. I do not know exactly why the aquifer suddenly came under pressure. I do suspect that the 6+ inches of rain we had received over the previous several weeks had something to do with it. An aquifer will show flowing artesian well characteristics depending on how it is being recharged and where the well is located in the aquifer. Please see the following website for more information on a artesian type of well: http://en.wikipedia.org/wiki/Artesian_aquifer
We presented the owner with three choices to prevent the flowing well from creating a flood in his yard since it is hard to tell when the well would stop flowing. There is a special water tight well cap made for this type of situation, but this is fairly expensive. We could try to raise the top of the well up. If we can raise the top of the well up far enough to get gravity to overcome the pressure of the aquifer, the well would stop flowing. This is a very inexpensive job, but it won’t look as nice in the yard. The last option is to route excess water to a storm drain with a pipe and check valve. This is also an expensive option and could allow contamination of the well if the check valve fails. The well could continue to show these characteristics for only a couple days or permanently.
Ultimately, the clients choose to raise the top of the well up. His well is located in the back yard so he was not as concerned about the appearance. The trick was going to be how high we would need to extend the top of the well. We got lucky and the water stopped flowing out of the well casing once we added 4’ of casing. This made the top of the well about 5’ tall total. Is this normal? Most residential wells will never experience this in our area, but once in a while we get a well that is tapped into an aquifer that becomes pressurized enough to push water to the surface. This pressurization can be a sporadic, constant, or a onetime thing. Pressurization can also be a seasonal or weather regular occurrence. There is nothing wrong with a flowing well as long as the right steps are taken to prevent contamination and prevent flooding.