Integrated Solar Cooking

WAPI Contact Solution Provider

Solution Overview & Benefits

WAPI stands for Water Purification Indicator. WAPIs are small, handmade devices that tell you when water has reached 146 degrees F, the minimum temperature required for pasteurization. Once pasteurized, water is microbe-free and safe to drink. Water-borne illnesses cause diarrhea, which one of the leading causes of death in the developing world. Children are more susceptible than adults to such bacterial infections. Typically, water is left out in the sun or placed in a solar cooker to reach critical pasteurization temperature. Without a thermometer though, it is impossible to know if that water is truly safe to drink. The WAPI contains a slab of soy wax that melts at precisely the same temperature at which water is pasteurized. If the wax is solid, the water is not ready; when the wax has liquefied and collected at the base of the WAPI, the water is ready. The device fits in your pocket and is attached to a string for retrieval after purification. The simple design allows anyone to use it, while reinforcing the idea that water must be adequately boiled before consumption. WAPIs are reusable and can be assembled from spare manufacturing parts or kits.

History & Development

The Rotary Clubs of Fresno and Pacific Grove in California assemble WAPIs, distribute them around the world, and also offer WAPI-building kits from their website. They offer both “original” WAPIs, which use a PVC pipe frame, and a new WAPI that incorporates a stainless-steel wiring system. Both models are extremely effective. Each kit contains enough materials to construct 200 WAPIs. The website also contains highly detailed instructions on how to build your own WAPI, and where to find its component materials. Soy wax can also be purchased through the Rotary Club. Please contact Walt Parrish for more information at [email protected].


Publicly available: yes
Countries where available: Worldwide
Price range (USD): 1 to 20 USD
Available online: yes
Offered or can be licensed for local manufacture: Yes
Countries where spare parts can be purchased: Worldwide

Additional Information

Product Webpage (external link)


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