Iron and orange staining
Iron dissolves out of the ground into well water. It is clear coming out of the tap, then turns orange or brown once it meets air, which is why it shows up as stains on fixtures and laundry.
It is one of the most common reasons a well owner calls.
Sulfur and the rotten egg smell
A smell of rotten eggs, strongest in hot water, points at sulfur. It can come and go with the seasons and the water table.
It is handled at the point of entry so the smell does not reach the showers.
Sediment and grit
Sand and grit from the well wear out valves and clog aerators and screens. A sediment stage catches it before it reaches the rest of the system.
It also protects the stages that come after it.
Hardness on a well
Well water is often hard as well as everything else, and the scale it leaves is the same as on city water.
When it is, softening goes into the lineup alongside the other stages. How softening works.