Heat the grill. Heat a gas grill for high direct heat, about 450°F. If you are using a charcoal grill, prepare one side for high heat and the other side for medium heat.
Prep the chicken pieces. Sprinkle the chicken pieces all over with salt, pepper, and garlic powder.
Make the sauce. In a small bowl or measuring cup, combine the water, vinegar, oil, and crushed red pepper.
Sear the chicken. Place the chicken pieces over high heat for 2 to 3 minutes on each side. Lower the heat to medium (gas grill), or about 350°F, or move the chicken to the lower heat side (charcoal grill). Brush the chicken pieces with some of the sauce.
Cook with the lid closed. Close the grill lid and cook for about 10 minutes.
Brush the chicken pieces. Open the lid and brush with more of the sauce. Turn the chicken over, close the lid, and continue cooking for an additional 10 minutes.
Continue cooking. Repeat brushing and turning 2 to 3 more times, or until the chicken tests done. The safe minimum temperature for chicken and other poultry is 165°F. Check in several places (not touching bone) with a reliable instant-read thermometer.