Using Hydrogen fuel is defined by IRS as using a "clean-burning fuel" (what comes out after the process is pure water). And the IRS has deep pockets. You can get back $2000 for a regular car and even $50,000 for a truck. Here is the exact quoted text from the IRS:

The electrical part is made by connecting the device to the 12 Volts of your battery via the ignition switch. This prevents hydrogen production when the engine is off and uses only 1-3 Amps!

Once you will get the SimpleWaterFuel packge, you will be able to see all the step-by-step details on how to do this yourself, in just a few hours.