Pieces of asbestos-cement pipes obtained from water distribution systems and laboratory investigations were studied with a scanning electron microscope, an X-ray analysis unit, and two types of hardness testing instruments. Rockwell 'L' hardness measurements and modified Shore 'D' durometer readings were found to be related to the depth to which calcium has been lost from a pipe exposed to aggressive water. The calcium loss was measured by an X-ray analysis technique performed in a scanning electron microscope. The modified durometer showed promise as a field instrument for determining the extent to which asbestos-cement pipe had been attacked by aggressive water.