As a result of cooling the air, air conditioners create condensation or water. Often there is a pan under the air conditioner to hold the water while it evaporates. You are better off installing a drain pipe to direct the water to either the sewer or outside.
If there is no drain pipe or if it has come loose or is clogged the water will overflow into the attic and will cause damage before it can be discovered.
The average cost of fixing a leak from an air conditioner is $5,000.