The average home has the usual drains like sinks and tubs. They're not the only drains, however. There are the ?other? drains, often hidden and out of sight. Both types are important and need periodic attention to keep working properly and running free and clear. Beyond the usual suspects -- highly visible and heavily used sinks and tubs -- potential troublemakers lurk in unseen quarters, such as the basement. Look for a floor drain. They have traps that hold water and keep sewer gas out of the house. When drains aren't used, water evaporates out of the trap allowing all sorts of odor and trouble to come in. The solution is to pour water down the drain periodically. Always look for all sorts of hidden drains, as in central air conditioners and in frost-free refrigerators. Check often, and keep them running free. And that's the On The House tip for today.