Yesterday, I went to another customer's home because she had no hot water. With the thermostat turned most of the way up the water temperature barely made it to 94 degrees.
I verbally indicated, as well as wrote down that the furnace and water heater were vented into an unlined chimney (they didn't have a flex liner as required by code) as well as a leaking dielectric union at the water heater itself. The utility doesn't cover plumbing as of yet, nor venting but are legitimate safety concerns as there was no inspection sticker on any of the equipment. Fast forward to today, I brought in the part and the customer proceeded to chastise me that she didn't need a liner because the chimney was "too old" and that the water heater wasn't leaking. I promptly took photos of the house outside (which I cannot show for privacy reasons) as well as the venting, placement of the furnace and water heater, the absence of their inspection stickers, and the venting which was in 4 inch single wall for the furnace and three inch single wall for the water heater. Both were vented in different sides of the chimney; making placement of a flex liner impossible.