Here are some free resources to learn all about water, starting with this activity that demonstrates desalination.
Water Use and Conservation: Activities and videos.
Estimation and Graphing Activity:
Free Notebooking Activity:
Water In Our Daily Lives: Lessons, worksheets, and animation describing where water comes from, and how it moves and is affected by different factors, like runoff. The learning material uses New York City as an example, but suggests how to adapt it to any city or town.
Science Concepts Learned From Water:
Click here for more free ecology resources.