What are common signs of a gas leak in a residential setting?

The presence of a gas leak in a residential setting is most commonly indicated by a distinct smell likened to that of rotten eggs, which is deliberately added to natural gas for safety reasons, given that natural gas is odorless in its natural state. This sulfur-like odor serves as a crucial warning sign. Additionally, hissing sounds may occur as gas escapes from a pipe or fitting, further indicating an active leak. These two signs together create a significant alert, prompting individuals to take immediate action to ensure safety.

The other options, while they may suggest issues in a home, do not provide the same immediacy or clarity as the smell and sounds associated with a gas leak. Increased heating bills could suggest inefficiencies in the heating system or increased usage, but they do not specifically indicate a gas leak. Frequent appliance breakdowns may point to various maintenance issues but are not direct indicators of gas leaks. Similarly, visible rust on gas pipes can indicate deterioration but does not necessarily confirm a current leak situation; it can be a sign of potential problems in the future. Thus, the most direct and reliable signs of a gas leak are indeed the smell of rotten eggs and hissing sounds.