In New York City, septic system installation & replacement work generally requires a permit when the project exceeds $200 or involves system replacements. Your licensed contractor should pull the permit — if they ask you to pull it yourself, that's a red flag. Unpermitted work can cause problems when selling your home.
Full Explanation
New York City follows NY state building codes administered by the local building department. Permit fees vary by project value. All inspections must be scheduled through the New York City building department. Keep all permit documentation — required for home resale disclosure.