Water is precious. It is also easy to take for granted. Many people recognize that water is scarce in desert areas. but it is harder to realize that places like Massachusetts could face a shortage of pure drinking water. This manual provides teachers with curriculum resources to introduce concepts of water supply and water conservation to third and fourth grade students. The lesson units are designed to provide a background in basic environmental principles necessary for students' understanding of where safe drinking water comes from and why it is important to conserve water. This guide contains five lessons, each of which introduces a water concept. Each lesson includes: (1) background information; (2) key concepts; (3) lesson plan objectives, procedures, vocabulary, and tips for teaching; and (4) several hands-on activities. Reproducible student worksheets are included. Additional resources are listed in the back of the guide. (CW)