What is the minimum water supply diameter and the maximum pressure allowed?

The minimum water supply diameter of 3/4 inch and a maximum pressure of 80 psi is correct because it aligns with plumbing standards aimed at ensuring adequate water flow and pressure for residential and commercial applications. A 3/4 inch diameter is typically sufficient to provide the necessary volume of water for most fixtures, while the 80 psi limit helps prevent issues such as pipe bursting or excessive wear on plumbing fixtures. Maintaining pressure at this level ensures both effective operation of fixtures and durability of the plumbing system, contributing to overall efficiency and functionality in water supply systems.