What is the minimum internal diameter, in inches, for condensate waste and drain lines?

The minimum internal diameter for condensate waste and drain lines is commonly standardized to ensure that adequate drainage occurs without the risk of blockage or overflow. For many HVAC installations and plumbing systems, a diameter of 3/4 inch is sufficient to handle the typical flow rates of condensate, which generally consists of water produced from dehumidification processes or air conditioning units.

Choosing 3/4 inch as the standard minimum size helps balance the requirements for efficient drainage with the need to prevent clogs that might occur with smaller diameters. An established minimum size also ensures compliance with various building codes and installation guidelines that govern plumbing systems. While larger diameters may be used for specific applications that involve increased flow or longer horizontal runs, 3/4 inch remains the baseline for typical condensate drainage scenarios.