New Jersey State Law requires that you must call the New Jersey One Call System before you dig (excavation, demolition, etc.) whether it’s a small or a large construction or homeowner project (such as putting up a fence, mail box post or real estate sign post, building a home addition, deck or foundation, etc.) for marking underground utility lines. Calls must be made 3 business days in advance, but no more than 10 business days. Excavation must commence within 10 business days. Operators are available 24 hours a day, 7 days a week.