My house is in a rural area and water is supplied from a well that was hand dug many years ago. It is 18-20 ft deep. We have alway had good water, and plenty of it. Looking in the well the water is very clear. We have the pump, pressure tank in the basment setup. Lately we have been getting more and more small black particles in our water. They don't stain our cloths but when rubbed between your fingers they leave a faint brown/black streaks. These particles clog our facets, toilet valves and making it impossible to drink the water. At times the particles are much worse and other times we hardly see any. We have had a well tech out but he seems unsure of where the particles are coming from or what is causing them. I am looking at installing a whole house fiter but need to fix the source of the problem also. Anyone ideas would be greatly appreciated!!!