In this paper I draw on the rich colonial archives of Mexico to explore how anxieties over climate variability and specifically droughts, were articulated in legal proceedings over natural resources. There are thousands of lawsuits (pleitos) from the colonial period charting instances of illegal water use, water monopolisation, diversion, water theft, deprivation and usurpation and requests for reinstatement of water rights and all cross-sections of society appear to have been involved in water disputes at some stage throughout the colonial period. The degree of antagonism over this most essential resource, however, appears to have been exacerbated by drought, while a fear of water deprivation or perhaps memory of the impacts of drought induced scarcity underpinned many of the documented water disputes. In as much as there may be some association between drought and an escalation in disputes over water, I wish to demonstrate that there was a strong element of opportunism in water litigation, and an awareness of the propensity for drought and its impacts may have been employed by litigants as a legal “tool” to reinforce or refute claims of water shortage, monopolisation, deprivation and/or restitution.