Preheat the oven to 425 degrees F (220 degrees C).

Combine chicken, potatoes, tomatoes, pesto, water, olive oil, salt, and pepper in a large roasting pan; mix well.

Bake in the preheated oven until chicken is no longer pink at the bone and juices run clear, about 45 minutes. An instant-read thermometer inserted near the bone should read 165 degrees F (74 degrees C).