Sand in a water well indicates silt and sand filling in the bottom of the well, degradation of the filter screen, too large a pump, or the pump being located too close to the bottom of the well. A well technician is able to help owners find solutions to these problems.
Over time, sand and silt infiltrate the well and settle to the bottom. Eventually the level increases to the point the pump stirs the silt, and it draws sand along with the water it forces from the bottom of the well. This sand causes premature wear of the pump parts, eventually leading to pump failure. Sometimes the well technician is able to reposition the pump to a higher location, keeping sand out of the water supply. This solution also helps when the pump is originally set too close to the bottom of the well.
The well casing has openings that allow water to filter into the opening while keeping sand, gravel and soil out of the well. If this filter begins to degrade, sand washes into the well and the water supply. If the well is large enough, it is sometimes possible to add a separate filter around the pump, but this problem requires replacing the well casing. Sometimes the solution is to cap the existing well and drill a new one.