When disasters disable drinking water infrastructure, communities often require more than short-term bottled supplies; they need reliable volumes of safe water for daily needs over weeks. The Water-on-Wheels Mobile Emergency Water Treatment System, known as the WOW Cart, was created to address that gap through a partnership between the U.S. Environmental Protection Agency (EPA) and the nonprofit WaterStep, formalized under a Cooperative Research and Development Agreement. In this collaboration, WaterStep designed, engineered, and fabricated the unit, while EPA contributed technical assistance, environmental sampling, and disinfection research, including practices for granular activated carbon (GAC) and ultraviolet (UV) treatment.
Portability and rapid readiness are central to the unit’s design. Weighing under 500 pounds, the WOW Cart fits in the back of a pickup truck and can be moved by two people. It is straightforward to operate, enabling local volunteers to be trained on-site rather than waiting for specialized crews. This approach is intended to speed deployment and continuity of safe water production immediately following a disruptive event.
The treatment process integrates multiple barriers. Pre-filtration is paired with either granular activated carbon or ion exchange media, followed by on-site chlorine gas generation using ordinary table salt, and UV-C disinfection. The cart can run on generators, batteries, or solar panels, supporting flexible use in power-constrained settings. At full output, the system can produce up to 10,000 gallons per day, with treated water conveyed to a folding 1,250-gallon bladder tank.
Since 2020, WOW Carts have been deployed nationally and internationally. Notable responses include post-disaster operations after Hurricane Laura in Louisiana and support during a series of tornado and flood emergencies in Kentucky. These field uses reflect the unit’s role as a stopgap when centralized systems are damaged or when distributed treatment is needed to bridge recovery.
EPA’s Region 7 most recently showcased the technology on September 18 at an event in Lawrence, Kansas, held with the Kansas Rural Water Association, WaterStep, and FEMA during National Preparedness Month. The demonstration emphasized preparedness and the value of having resilient, rapidly deployable treatment options available before a storm or other hazard impacts service.