The water tower has been updated to v0.16.4b - this update includes the Security system in the owner menu.
You will get an update request automatically on your land, you can also force an update by picking up the tower and rezzing it back out, as the old towers still use the Casper system.
NOTE: If you are not getting an update request, this is likely due to a throttle limit on the Casper Server end and you will have to wait until later.
New Tutorial Video:
