Master Plumber Practice Exam 2025 – Complete Prep Guide

The standard sizes for residential water service lines typically range from 3/4 inch to 1 inch. These sizes provide a good balance between water pressure and flow rate for most household needs. A 3/4 inch pipe is commonly used for smaller homes or those with less demand for water, while a 1 inch pipe can accommodate larger households or higher water usage situations, such as multiple bathrooms or irrigation systems.

Choosing a pipe size larger than 1 inch may lead to unnecessarily high material costs and could complicate installation without providing significant benefits to water delivery in a typical residential setting. Options for smaller pipes, such as 1/2 inch, could lead to inadequate water pressure or flow for multiple fixtures being used simultaneously. Meanwhile, larger sizes like 1.5 inch or 2 inch are more appropriate for commercial applications or larger building projects, where higher flow rates are required.