This guideline presents procedures that can be used to evaluate the probability of earthquake damage to water transmission systems. This document was developed to address the lack of a consistent assessment methodology within industry, consulting, and academic communities. The lack of consistency prevents direct comparison of damage estimates for prioritizing where resources can best be allocated to mitigate damage. The raw damage data supporting the fragility relationships are included with the guidelines to facilitate the addition of new information from future earthquakes. Use of these fragility data will allow water system owners to estimate the vulnerability of their systems and to make informed decisions to mitigate risks.