We (i.e., my student K. Pavlakis and I) have studied the interaction of H2 0 masers in star forming regions as a physical mechanism for the explanation of the very strong H20 maser sourses. We have carried out detailed numerical calculations for both saturated and unsaturated masers and have derived approximate analytic expressions for the expected brightness temperature from interacting masers. We have found that the interaction of two low or medium power masers can in principle lead to the appearance of a very strong one.