AquaPak is simple water pasteurization device employing solar energy.

The AquaPak employs PE bubblewrap sheeting as a heating source. When exposed to direct sunlight, each of the air-filled transparent bubbles acts as a miniature greenhouse, creating heat.

In shape of a pocket, the bubblewarp serves as a compartment for filling in and heating water.
A wax indicator announces when the desired temperature is reached; the orange wax in the indicator is placed in a small, sealed glass cylinder that is attached to the cap for closing the water compartment. When the wax melts at 67°C, it looses its color. After maintaining this temperature for a few minutes, most disease-causing organisms are eliminated, the water is pasteurized and is drinkable.

The Aquapaks are very cheap to manufacture in developing countries at one dollar a piece.

The acceptability of the Aquapak has been tested in a rural community in El Salvador. After a training session was held, 30 Paks were distributed, 26 to family homes, one to the school, one to a meeting house and two to the local health promoter. The usage of the Aquapaks was observed in subsequent visits. After the first visit, there were still 24 families employing the device and two still needed to be convinced of its benefits, after the second training sessions, every household continued usage.