Preheat the oven to 325 degrees F (165 degrees C).

Season chicken with salt and pepper; place in a large roasting pan. Arrange onions, potatoes, carrots, and celery around chicken. Pour water into the pan. Cover the pan tightly with aluminum foil.

Roast in the preheated oven, basting occasionally, until chicken is golden brown, about 2 hours; remove aluminum foil for the last 30 minutes of cooking. An instant-read thermometer inserted into a thigh should read at least 165 degrees F (74 degrees C). Allow chicken to rest for 10 minutes before carving.