Identification

• An air-conditioning secondary drain is a backup pipe that provides an alternative path for overflow condensate.
  
  

Significance

• If the primary drain line becomes blocked with dirt or sludge and the air conditioner does not have a secondary drain, water can leak from the unit and damage or stain floors and ceilings.
  
  

Maintenance

• The secondary drain should be cleaned and flushed with water periodically during the cooling season to prevent blockage.
  
  

Expert Insight

• "Insurance companies look favorably on secondary drains. This shows that the property owner has taken the necessary precaution against water damage to the property," said Elvet Richardson, HVAC instructor at Technical Career Institutes in New York City.
  
  

Warning

• According to professional home inspector Barry Stone, capping a fitting where a secondary drain pipe should be attached is a code violation in some states.