In this article you will learn how to use a water level for all of your projects where it is important to maintain a specified height over a large area.
The fluid in the water level will find its own level.
So set up the level of the water inside the bottle to the desired height.
For instance, level with the transom board for a deck.
Where ever you locate the tube at the other end the water level will be equal.
This could be used to judge the height of your deck posts to assure the finished deck surface will be plumb and level.