This paper presents the computation procedures for estimating average annual water yields based on annual precipitation and vegetation cover types. This procedures allows for an estimation of water yields under current conditions, under various levels of vegetation management, or under historic water yield based on fire history. Two examples of evaluating fire's role in determining annual water yield in mountain watersheds in the USA are presented. Annual water yield was estimated using developed procedures for the Tenderfoot Creek Experimental Forest in central Montana for the past 400+ years based on fire history records. Additionally, the increase in runoff for 11 years after the 1988 fires in Yellowstone National Park, Wyoming, was estimated using runoff-forecasting equations developed with prefire data, and this was compared with the analytical procedures similar to Tenderfoot Creek.