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The devastating 2018 Camp Fire unleashed an urban firestorm in Paradise, California, resulting in the destruction of over 18,000 structures. While it is known that runoff from burned wildland areas contains ash, which can carry contaminants including metals into nearby watersheds, the effects of wildland urban interface (WUI) fires, such as the Camp Fire, on surface water quality remain poorly understood. This study investigated the impacts of extensive urban burning on surface water quality in major local watersheds. Over a period from November 2018 to May 2019, nearly 150 samples were collected, comprising baseflow and stormflow from burned and unburned downstream watersheds with varying levels of urban development. Samples were analyzed for total and filter-passing metals, dissolved organic carbon, major anions, and bulk water quality parameters, with a subset of samples analyzed for particle size distribution. Our findings reveal that ash and debris resulting from the Camp Fire contributed to elevated metal concentrations in downstream watersheds through stormwater runoff. Total concentrations of Al, Cu, Cd, Pb, and Zn exceeded EPA aquatic habitat acute criteria by up to 16-fold. Metals were found mostly associated with larger grain sizes (>0.45 µm), however Al, Cr, Fe, and Pb exhibited a significant colloidal phase (<0.45 µm). This study underscores the impact of wildland-urban interface fires on nearby affected watersheds, as evidenced by increased metal concentrations. These findings highlight the potential ecological consequences associated with such fires, emphasizing the importance of understanding and addressing the long-term effects of WUI fires on surface water quality.