A rainwater catchment system is a series of pipes and tanks designed to collect rainwater and store it for other purposes. Most commonly, rainwater catchment systems are gravity-fed and store water in large tanks. Common types of catchment systems include those that use a gutter system to collect rain falling on a roof, and a channel system to collect rain falling on the ground.

Rainwater can be used in a full range of domestic purposes, depending on its purity and how it is collected.

Rainwater Catchment in the arctic climate

It is possible to engineer rainwater catchment systems which will perform well at a reasonable cost. Rain accumulation is often limited by long winters, however during the warm seasons the benefits can still offset the costs. The amount of rain is dependant on regional climates, and, on the whole, coastal areas will receive more rain than interior regions.

Storage tanks can be manufactured from a broad range of materials, the more conventional choices being fiberglass, wood, steel, concrete, and a variety of plastics. Each type has advantages and disadvantages, with plastic tanks being the most prevalent type sold commercially in Alaska. Outdoor tanks and lines need to be insulated to protect from freezing. Buried tanks should be at least four feet below grade and are often protected by a top layer of insulation to prevent freezing. In those situations where the water will be collected for human consumption, an enclosed tank is highly advised to reduce the risk contamination.

The less trees and brush in the area, the cleaner the collected water will be. Surrounding trees can be removed to decrease the amount of pine needles, seeds, and leaves that get into the water supply or enter gutters. Gutters should be cleaned regularly to prevent standing water which is capable of contamination from a number of organisms, including mosquitos.