Could the pressure in an artesian well that is shut down over the winter exceed the capacity of the pipes when the overflow drain is closed and then opened again in the spring?
The water you get from an artesian well—which has been drilled down into an aquifer—flows naturally as a result of hydrostatic pressure that forces it to the surface. The pressure pushing the water out of the earth is greater than the force of gravity pulling it down. In the winter, when the water isn’t going to your cottage, the overflow pipe allows any excess to trickle out. But there’s no reason to think the pipes and fittings in your well are going to burst when you shut off the overflow; the minimum pressure capacity for CSA-approved water pipes is 75 psi. If you’ve followed the same shut-down procedure for years without problems, keep doing the same. However, if your overflow drain were to become obstructed in winter, water could spill over the top of the well, causing erosion in the surrounding earth, and frost damage to the well and the fittings and pipes inside. But don’t panic. This scenario is very unlikely.