Performed heater tune-up on a Carrier heat pump and two York gas furnace systems. Checked the electrical, mechanical and performance systems of the unit. Cleared, cleaned, flushed and treated the drain lines and washed the outdoor heat pump coil. I did find a lot of water sitting in the basement. It looks like the main drain that goes under the home was clogged. This is where the a/c systems drain out as well. I was able to partially clear the main drain and remove the water from the basement. Talked to the homeowner and recommended having a plumber out to help prevent the water from backing up again. No other issues found. All systems are operational at this time.