If you notice pooling water in your basement and haven't experienced heavy rains that could cause flooding, your first instinct will be to check to make sure one of the water supply lines isn't leaking. But if you can't trace the water back to a supply line source, there are a couple other potential causes.
If you have a flat basement floor, you'll likely be able to easily identify where the water is coming from. But, if your basement floor slants so that the water can run, you might have to trace the liquid back to its source.
Leaking Drip Pan in Furnace
If your home has a central HVAC system, the furnace inside your home—likely in the basement—contains the air handler portion of the air conditioning system. The air handler holds evaporator coils that become cold when taking in liquid refrigerant. The chilling of the coils provides the source for your home's cold air but also produces condensate. The condensate drops down into a drain pan.
The drain pan empties into a drainpipe through either gravity, if the unit is situated with enough of a tilt for the water to run off on its own, or through the workings of a mechanical condensate pump. If any part of this process fails, your drain pan can overflow and leak out onto the floor.
Check to see whether the drain pan is emptying at all. If the pan doesn't empty and you have a gravity system, the drainpipe is blocked and you need to call in a drain cleaning plumber. If you have a condensate pump system, call a plumber to test the part and see if the pump needs replacing.
Leaking Water Heater
Water can naturally drain down around a water heater if the temperature and pressure relief valves release occasionally to balance the system. Water heater units often have a small drain pain under the tank to collect dripping water. But, if the temperature and pressure relief valves go off excessively, the pan can overflow and the water heater could be unstable.
If the water leaking seems to come from the tank itself rather than the pressure valve, your tank has experienced so much mineral erosion that it is no longer stable. Either of these water heater issues merits an emergency service call from a plumber and perhaps the immediate replacement of your water heater if the situation is dire.
If you have questions about either of these issues or the water on your basement floor seems to be coming from somewhere else, talk with a company like Backlund Plumbing.