Context :

Aims : We have searched for emission from the 557 GHz ortho -water line in the interstellar medium of six nearby starburst galaxies .

Methods : We used the Odin satellite to observe the 1 _ { 10 } -1 _ { 01 } transition of o -H _ { 2 } O in the galaxies NGC253 , IC342 , M82 , NGC4258 , CenA , and M51 .
None of the galaxies in our sample was detected .

Results : We derive three sigma upper limits to the H _ { 2 } O abundance relative to H _ { 2 } ranging from 2 \times 10 ^ { -9 } to 1 \times 10 ^ { -8 } .
The best of these upper limits are comparable to the measured abundance of H _ { 2 } O in the Galactic star forming region W3 .
However , if only 10 % of the molecular gas is in very dense cores , then the water abundance limits in the cores themselves would be larger by a factor of 10 i.e . 2 \times 10 ^ { -8 } to 1 \times 10 ^ { -7 } .

Conclusions : These observations suggest that detections of H _ { 2 } O emission in galaxies with the upcoming Herschel Space Observatory are likely to require on-source integration times of an hour or more except in the very brightest extragalactic targets such as M82 and NGC253 .