"Framework for K-12 Science Education" states that "children are natural engineers … they spontaneously build sand castles, dollhouses, and hamster enclosures and use a variety of tools and materials for their own playful purposes" (NRC 2012, p. 70). The "Next Generation Science Standards" ("NGSS") also supports engineering design in the K-2 grades, where students are "introduced to problems as situations that people want to change." They use tools and materials to solve simple problems, use different representations to convey solutions and compare different solutions to a problem, and determine which is best" (NGSS Lead States 2013, Appendix I, p. 105). Thus, it is imperative that engineering practices be introduced in early grades so that students have opportunities to develop creative, critical thinking processes to solve problems. This article describes how a science teacher educator, a water company informal educator, and a second-grade teacher-developed and co-taught a three- to four-day instructional unit within the authentic context of water filtration.