  Aim: We present an improved database of temperature dependent rate
coefficients for rotational state-to-state transitions in H$_{2}$O + H$_{2}$O
collisions. The database includes 231 transitions between the lower $para$- and
210 transitions between the lower $ortho$-states of H$_{2}$O (up to $j=7$) and
can be employed for cometary and planetary applications up to the temperature
of 1000 K.
  Methods: New general method is developed and applied which permits to
generate rate coefficients for excitation and quenching processes that
automatically satisfy the principle of microscopic reversibility and, also,
helps to cover the range of low collision energies by interpolation of cross
sections between the process threshold and the computed data points.
  Results: It is found that in the range of intermediate temperatures, $150 < T
< 600$ K, new rate coefficients are in good agreement with those reported
earlier, but for higher temperatures, $600 < T < 1000$ K, the new revised
temperature dependence is recommended. The low temperature range, $5 < T < 150$
K, is now covered, by the abovementioned interpolation of cross sections down
to the process threshold.
