How do i contact ntua navajo tribal utility authority? Contact NTUA Navajo Tribal Utility Authority PO Box 170, Fort Defiance, AZ 86504 928-729-5721 or 1-800-528-5011Where can i find the telephone numbers of ntua services? The telephone numbers of all Departments, Sections, Laboratories, Secretariats and the rest of NTUA Services, as well as those of the NTUA staff are found in the electronic directory service.What does ntua stand for? The Navajo Tribal Utility Authority (NTUA) was established on January 22, 1959, to address the absence of utilities on the 27,000 square-mile Navajo Nation. Since then, NTUA has grown into a self-sustaining, not-for-profit, successful tribally-owned enterprise.How do i contact ntntu? NTU: Contact NTU: University Contact Information. NTU_PageContent. . Mailing Address. Nanyang Technological University. 50 Nanyang Avenue, Singapore 639798. *Please refer to the contact list below and attention it to the respective department / office in charge. Contact Number. Tel: (65) 67911744.