Petra Wadström (born 20 February 1952) is a Swedish inventor of a water purification device called Solvatten, which is a portable device that heats and purifies dirty local water in locations with access to significant amounts of sunshine.

[2] After returning to Sweden, she designed and built a device resembling a portable black container that opens like a book in direct sunshine to maximize the effect of the sun and UVB radiation.

During the invention process, she built prototypes at home and tested them using wastewater from local treatment plants.

By using the durable Slovatten unit, families who live off-the-grid can transform water from local sources, which may not be potable, into clean hot water that can be consumed safely warm or cold.

[3] Wadström is a founder and Senior Advisor of the social enterprise Solvatten AB, which was established in Sweden in 2013 to expand access to the device around the world.