Climate hazards expose distinct compliance vulnerabilities in US drinking water systems

Climate hazards expose distinct compliance vulnerabilities in US drinking water systems | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Climate hazards expose distinct compliance vulnerabilities in US drinking water systems Chris C. Lim This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9217282/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Climate extremes threaten drinking water systems. Whether climate hazards compromise drinking water regulatory compliance, and through which pathways, remains uncharacterised at national scale. We linked extreme precipitation, heat intensity, and wildfire smoke PM2.5 to monthly Safe Drinking Water Act violation risk across twelve contaminant categories in 56,351 community water systems (2006–2020). Extreme precipitation produced the broadest disruption, increasing turbidity, coliform, disinfection byproduct and treatment-technique violations by 8–13%, concentrated in surface-water and smaller systems. Heat showed a narrower, microbial-specific signal: Escherichia coli (E. coli) violation risk increased ~2.6% per °C, though the pathway could not be mechanistically isolated. Wildfire smoke associations were fragile: pooled estimates attenuated under strict seasonal controls, and only an exploratory transport-distance probe remained positive. These findings reveal a graded evidence hierarchy, precipitation robust, heat selective, smoke provisional, arguing for climate-responsive monitoring triggers matched to hazard-specific evidence strength, including post-precipitation follow-up for smaller systems. Earth and environmental sciences/Hydrology Earth and environmental sciences/Climate sciences/Hydrology Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9217282","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":611934616,"identity":"9bf7a254-b519-4fb6-ab66-cad7adeaf793","order_by":0,"name":"Chris C. 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