What size pipe is most commonly used for branches feeding multiple fixtures?

The most commonly used pipe size for branches feeding multiple fixtures is 3/4". This size strikes an effective balance between providing sufficient water flow to supply multiple fixtures and minimizing water pressure loss. When multiple fixtures need to draw water simultaneously, a larger pipe like 3/4" can help ensure that each fixture receives adequate pressure and volume without excessive restriction.

Using 1/2" pipe may not provide enough flow when multiple outlets are being supplied, potentially leading to decreased performance or inadequate water supply. On the other hand, while 1" and 1 1/2" pipes can certainly handle multiple fixtures, they may be unnecessarily large for typical residential applications, leading to increased material costs and more complexity in installation when 3/4" adequately meets the demand. Thus, the 3/4" pipe is typically the most practical choice for branching off to several fixtures.