It is very likely that your eyes become fatigued which a common cause of watery eyes is. It means that your eyes need a break. Looking out a window at something distant regularly is the best way in my own personal experience. Watery eyes can also result from a symptom from some type of allergies, a sinus infection, headaches, irritations, or even problems with eye-wear such as contacts. In your daily time, you should keep your home clean from any dust, dander, and household plants to prevent your eyes from allergies. Each problem is different, and should be investigated individually. So once it becomes serious, you should go to see a doctor right now.