In the past ten years, smart irrigation controllers have been developed by a number of manufacturers and have been promoted by water purveyors in an attempt to reduce excessive irrigation. Legislation has been introduced in California and Texas and passed in Florida mandating or incentivizing the use of these controllers. As a result of the interest in smart controllers, their use is increasing in new installations and retrofits of residential and light commercial irrigation systems. A number of controlled research studies using formal experimental design and statistical analyses indicate substantial water savings of anywhere from 40% to more than 70% when using these devices; however, real-world savings in larger pilot-scale projects indicate savings of typically less than 10%. Reasons for the divergence between the apparent potential savings and the realized savings in pilot projects are related to the lack of: targeting of high irrigation users (on either a relative or absolute scale), education for contractors and end users, and timely follow-up to assess water savings. In addition, much of the scientific research on smart controllers has been conducted in humid regions where higher potential savings are likely due to irrigation needed only to supplement rainfall. Future pilot projects should include comprehensive educational components aimed at irrigation sites with potential irrigation savings based on estimated landscape irrigation demand from climatic variables (i.e., high irrigation users).