Trick for a Moist Cake

      A co-worker of mine brought a Cinnamon Streusel cake into work the other day and it was wonderful. Cinnamon Streusel cakes tend to be on the dry side; however, her little secret for a moist streusel cake is as follows: 

              Replace milk for the water in the recipe.

      She did tell me that she uses a box mix and that she replaces milk for the water.   I tried this in a regular chocolate cake box mix and it worked beautifully.  However, I don't know if it will work in a cake made from scratch.   If anyone out there tries this with a homemade cake recipe then let me know the results.  I would greatly appreciate it.

Thanks!