What is the minimum drain size for residential sinks with garbage disposal?

What is the minimum drain size for residential sinks with garbage disposal?

• A. 1 inch
• B. 1 1/4 inch
• C. 1 1/2 inch
• D. 2 inch

Answer: (C)

When a kitchen sink has a garbage disposal, the drain must be large enough to handle the disposal’s flow and the solids it creates. The standard minimum for residential kitchen drains with a disposal is 1 1/2 inches. This size provides enough capacity to prevent frequent clogs and slow drainage while fitting typical traps and fittings. A smaller diameter would bog down with disposal use and increase the chance of blockages, while a 2-inch drain isn’t usually necessary for a standard home and adds unnecessary complexity. So, 1 1/2 inch is the best choice.

When a kitchen sink has a garbage disposal, the drain must be large enough to handle the disposal’s flow and the solids it creates. The standard minimum for residential kitchen drains with a disposal is 1 1/2 inches. This size provides enough capacity to prevent frequent clogs and slow drainage while fitting typical traps and fittings. A smaller diameter would bog down with disposal use and increase the chance of blockages, while a 2-inch drain isn’t usually necessary for a standard home and adds unnecessary complexity. So, 1 1/2 inch is the best choice.