What is the typical fixture unit range for washing machine or dishwasher?

• A. 1-2 FU
• B. 3-4 FU
• C. 2-3 FU
• D. 4-5 FU

Answer: (C)

Fixture units quantify how much water a fixture is expected to demand, and they’re used to size the supply piping. Washing machines and dishwashers use a moderate amount of water, mainly during the fill cycle, and they aren’t continuous draws. That combination places them in the middle range of the fixture-unit scale. So, the typical range for either appliance falls around 2 to 3 fixture units.

In practice, you’d add the fixture-unit values for all fixtures on a given supply to see the total demand and then reference the code’s sizing table to choose an appropriate pipe size. Using about 2–3 FU for these appliances helps ensure the line isn’t undersized during peak fill moments but also isn’t oversized for everyday use.