No water masers associated with supernova remnants

We have used the Very Large Array to search for water masers in the three s upernova remnants W28, W44, and IC 443. Only one candidate maser was detect ed, in W44. Follow-up observations using the VLA at 1612 MHz demonstrate th at the water maser in W44 is likely associated with a late-type star and no t a shock in the supernova remnant. The nondetection of water masers toward shocked regions in these supernova remnants places constraints on the post shock density and is consistent with the density determined by molecular ob servations and the limits from 1720 MHz OH maser pumping.