What is the drainage fixture units for a kitchen sink?

• A. 2 DFU
• B. 1 DFU
• C. 3 DFU
• D. 4 DFU

Answer: (A)

Drainage fixture units are a way to translate how much water a fixture will discharge into the drainage system so you can size pipes and vents appropriately. A standard kitchen sink is assigned two DFU, reflecting its typical discharge load. So the sink contributes 2 DFU to the drainage run. If you add other appliances that tie into the same drainage (like a disposal or dishwasher), those loads are added according to the code table, increasing the total DFU for that branch. The other options would apply to fixtures with different load values or to combinations that include additional fixtures on the same run.