In Alaska, the state owns all naturally occurring water, including rainwater before collection, under the prior appropriation doctrine established by Alaska Statute 46.15.010, which vests the Department of Natural Resources with authority to adjudicate water rights. Once harvested from a property’s roof or surface, rainwater becomes the private property of the landowner with no state regulations prohibiting collection for personal use.​
Water Rights System
Alaska follows a prior appropriation system for surface and groundwater use, where the first to beneficially use water from a source gains priority over later users. Significant diversions (e.g., over specified volumes defined in 11 AAC 93.035) require a state permit or certificate from the Department of Natural Resources, but rainwater harvesting for domestic, non-potable, or small-scale irrigation typically falls outside this as it does not involve diverting from natural streams or aquifers.​
Rainwater Harvesting Practices
No laws restrict rainwater harvesting in Alaska for potable or non-potable uses, and it is encouraged, especially in rural areas lacking public utilities. Systems must comply with local building codes for indoor use, including filtration and disinfection to meet health standards. Researchers recommend catchment for community water supplies, with best management practices outlined for safe collection and storage.​
Conservation Laws
Alaska promotes water conservation through its Water Use Act, prioritizing uses like domestic needs, sanitation, and irrigation while reserving water for fish, wildlife, and navigation. Rainwater harvesting aligns with these goals as a sustainable alternative, though large-scale commercial systems may need review for impacts on public water resources. No specific rainwater conservation mandates exist beyond general stormwater runoff rules under the Department of Environmental Conservation.
SOURCES
[1](https://www.ntotank.com/blog/rainwater-harvesting-laws-regulations-and-rights-by-us-state)
[2](https://www.rainwatercollection.org/regulations-by-state-details/alaska-rainwater-regulations-and-guidelines/r/reckFH4qLIM12alVM)
[3](https://www.arlis.org/docs/vol1/L/AlaskaWaterRights/Day1/B-Intro-to-AK-water-rights/Alaska-water-rights-basic-terms-concepts-processes-slides.pdf)
[4](https://law.justia.com/codes/alaska/title-46/chapter-15/article-1/section-46-15-010/)
[5](https://rowalaska.net/archives/projects/2016_access_law/Bennett/Resources/11._DNR/DNR_FAQs/water_rights.pdf)
