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 three (3) business days in advance, but no more than ten (10) business days. Excavation must commence within ten (10) business days. Operators are available 24 hours a day, 7 days a week. Call 1.800.272.1000 or 811.