What is the minimum depth under a bathroom sink to the back wall?

What is the minimum depth under a bathroom sink to the back wall?

• A. 12 inches
• B. 20 inches
• C. 15 inches
• D. 17 inches

Answer: (D)

The key idea is knee clearance for accessibility. When a sink is used by someone seated or in a wheelchair, there must be enough space under the sink for the legs to fit without hitting pipes or the back wall. The minimum depth from the back wall to the front edge of that knee space is 17 inches. That depth provides room for the knees and allows plumbing to be tucked in behind, while still keeping the area usable. Choices like 12 or 15 inches are too shallow to allow proper knee clearance, and 20 inches is acceptable but exceeds the minimum, which is why 17 inches is the correct minimum.

The key idea is knee clearance for accessibility. When a sink is used by someone seated or in a wheelchair, there must be enough space under the sink for the legs to fit without hitting pipes or the back wall. The minimum depth from the back wall to the front edge of that knee space is 17 inches. That depth provides room for the knees and allows plumbing to be tucked in behind, while still keeping the area usable. Choices like 12 or 15 inches are too shallow to allow proper knee clearance, and 20 inches is acceptable but exceeds the minimum, which is why 17 inches is the correct minimum.