Vihmavett

Vihmavett is the water formed when precipitation reaches the surface of the Earth. It includes rainwater from clouds that falls to land or water bodies and can be collected from surfaces such as rooftops and gutters. In many regions people use rainwater harvesting systems to capture and store vihmavett for later use.

The quality of vihmavett is variable. Pure rainwater is relatively free of dissolved minerals, but it can pick up dust, pollen, and atmospheric pollutants during its passage through the air and when it contacts surfaces. Because carbon dioxide dissolves in rainwater, it is typically slightly acidic, with a pH around 5.6 in pristine conditions; pollution can lower the pH further. If vihmavett is stored or comes into contact with contaminated surfaces, it may also contain debris, microbes, or chemical residues. For drinking or cooking, vihmavett should be filtered and sterilized to meet safety standards.

Collection and storage are central to vihmavett use. Roof-based catchment systems route water through filters into storage tanks, from which it can be distributed for non-potable purposes such as irrigation, toilet flushing, and laundry. Some systems incorporate more extensive treatment to enable limited or full potable use, depending on local regulations and treatment quality.

Environmental and practical considerations include reduced stormwater runoff, lower demand on centralized water supplies, and cost savings for households, balanced against the need for regular maintenance, filtration, and monitoring of water quality. Rainwater harvesting is an ancient practice that remains common in regions with variable rainfall or limited water infrastructure.