I've checked my HVAC system and there are no leakage nor am I due for a new heater.

This is on top of another invoice they sent us in January for $500 for a washing machine leakage that they said they made a mistake and voided it. 

But CO (carbon monoxide) gases are a real problem with heating systems, and the exhaust system (including any chimney) must be capable of preventing any leakage of that exhaust into the building.

@Amit M.For my portfolio of properties, which are NOT rent regulated at all, it will remain unregulated under the new rent control laws.These laws were made to stop the leakage of rent regulated apts from leaving that pool.

Well bottom line is I called a foundation guy and he walked down the steps and immediately saw the issue - a slightly bowed wall indicating hydro static pressure and that was where the leakage came from. 

The smell could be from a number of things - animals, prior water leakage, mold, gases.

During the inspection, It was discovered that the baseboard had a crack in it due to water leakage(in the basement), and with breaking away, slowly.The furnace wasn’t working at the time of inspection and there was a leak of water not from the unit was thinking of purchasing but from a different unit.

They are competing with residential homeowners but are a huge operation that might have more operational costs/$ leakage than they are seeing in a hot market like this.Anyway, I am not trying to convince you or prove I’m right.

I have an investment property in Cincinnati and was informed that there is some water leakage going on in the basement.

There were no signs of water leakage inside and no bowing to the internal foundation that can be seen.