A plumber is installing a new residential drainage system. A kitchen sink with two compartments is being installed, along with a dishwasher that discharges into the sink's drain. What is the minimum drainage fixture unit (DFU) value typically assigned to this kitchen sink assembly in most Canadian plumbing codes?

Question: A plumber is installing a new residential drainage system. A kitchen sink with two compartments is being installed, along with a dishwasher that discharges into the sink's drain. What is the minimum drainage fixture unit (DFU) value typically assigned to this kitchen sink assembly in most Canadian plumbing codes?

Answer options:

• 2 DFU
• 3 DFU
• 4 DFU ✅ 5 DFU

Correct answer: 5 DFU

Explanation: Most Canadian plumbing codes assign a drainage fixture unit (DFU) value of 3 for a single kitchen sink and typically add an additional 2 DFU for an attached dishwasher or a two-compartment sink, leading to a typical total of 5 DFU for a kitchen sink with a dishwasher. This accounts for the maximum probable discharge from both fixtures simultaneously. A single sink without a dishwasher would generally be 3 DFU.