Spatial analysis of boil water advisories issued during an extreme weather event in the Hudson River Watershed, USA

• Boil water advisory (BWA) is issued as a precautionary measure after heavy storms.
• We spatially analyze BWAs issued after a major storm in New York, USA.
• BWAs are positively associated with precipitation and septic systems density.
• BWAs are negatively associated with recent maintenance and population density.
• Land use, and infrastructure planning and maintenance are key to reducing BWAs.

Water infrastructure in the United States is aging and vulnerable to extreme weather. In August 2011, Tropical Storm Irene hit the eastern part of New York and surrounding states, causing great damage to public drinking water systems. Several water supply districts issued boil water advisories (BWAs) to their customers as a result of the storm. This study seeks to identify the major factors that lead water supply systems to issue BWAs by assessing watershed characteristics, water supply system characteristics and treatment plant parameters of water districts in the Mohawk-Hudson River watershed in New York. Logistic regression model suggests that the probability of a BWA being issued by a water supply district is enhanced by higher precipitation during the storm, high density of septic systems, lack of recent maintenance and low population density. Interviews with water treatment plant operators suggested physical damage to water distribution systems were the main causes of boil water advisories during storms. BWAs result in additional costs to residents and communities, and the public compliance of the advisory instructions is low, so efforts must be made to minimize their occurrence. Prior investments in infrastructure management can proactively address municipal water supply and quality issues.

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