My mom called and thought her hot water heater was broken as there was water all over her basement carpet. A friend went there to help her clean up, and said the water is coming from the bottom of the furnace. It is a natural gas furnace, and the furnace is still working. What is the problem and how can it be fixed asap. Thank you.

Does the house have a central air unit? If so there is an A coil which is attached to the furnace. This coil has a condensation drain hose. This hose can become clogged over time. When this happens, the condensation will drip down and collect at the lowest point. In your case, the floor. The hose can be cleared with an air compressor. I had this happen in my house and found about 30 gallons of water had collected. Let me know if this works.