Trevi - Help Center Delivery and pickup In-ground or Built-in Harmony Do I need a permit for the installation of my in-ground pool? 18 March 2022 15:57 Updated Yes. A building permit request must be made to your municipality along with the pool plan that will be provided by Trevi. The request must be made 4 weeks before the scheduled delivery week. See section Permit and Important Documents of the Work Description Requirements Document. In-ground Harmony Still Need Help? Contact us or Place a service call Delivery or Pick-up Contact us Trevi client or Future client Installation or Renovation Contract number or In-store receipt number We will contact you within 24 hours.