Water Heater Combustion

It means that when the water heater is operating, the combution gases are coming into the room instead of going up the chimney. Not a good idea. The heaters flue or the chimney may be obstructed, or their could be a large exhaust fan which is drawing air down the chimney. In any case, the first thing to do is purchase a carbon monoxide detector, and the next thing is to find out why there is not normal draft occurring to draw the gases up the chimney.: Recent home inspection revealed that there is a need to repair combustion gas spillage at water heater combustion air inlet. What does this mean and who should I get to repair it?