Service tax on monthly maintenance charges of warehouse

Assessee has build 10 warehouses and sold it, however the land title is still in name of Assessee. Assessee takes monthly contribution from these 10 warehouses towards common expenses like light bill and its repairs, watchman charges, water charges and other common repairs and maintenance. These collection towards maintenance expenses comes to Rs.12 lakhs and more for FY 13-14.

Whether assessee is liable to service tax on these monthly collection of maintenance charges from warehouse owners?