Sometimes there are defects in a house that the homeowners no longer notice, such as small leaks in the roof or a basement that only gets damp when it rains. When the house is on the market, they don't have a real sense of urgency about having such defects repaired. The real estate agent feels quite differently, however.
When buyers are deciding which houses deserve serious consideration, any kind of water problem may appear to be much more detrimental than it really is. The sellers may regard a damp basement as simply a sign that it's time to clean the gutters or check the soil buildup around the house or a leaking roof as a call for new flashing. But to someone who has never owned a home, these defects can be taken as signs that the house may not fulfill their primary need for shelter from "the elements." Renters may be perfectly willing to live in a home with minor water problems, but buyers are likely to pass up the same house if they think it won't keep them perfectly dry.