Another option:
Using the dimension tool the last construction method on the right is ELEVATION.
After placing, select ONLY the TEXT and open the settings box.
The Autotext allows you to choose the option for "Sea Level". With it you can also either write in in the CUSTOM TEXT box "Sea Level" or choose the ALTITUDE autotext.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"