We get our water from a well. We have started geeting sand in the cold water and not the hot. I am afraid this means sand building up in the hot water heater. What could be causing the sand to be sucked up?

Could be drop in water table but more likely (unfortunately) the well is caving in. Might clear up by it self, might not. Flush water heater frequently to clear sand build up. Not point in having to replace water heater also.