A small mirror of the kind carried in purses can be helpful in diagnosing toilet clog problems. If the toilet becomes clogged, position the mirror so it reflects up the drainway. Then shine a flashlight on the mirror to see if a foreign object like a child's toy is causing the problem.
Pay special attention to carpet on concrete floors. Carpet can absorb moisture and serve as a place for biological pollutants to grow. Use area rugs which can be taken up and washed often. In certain climates, if carpet is to be installed over a concrete floor, it may be necessary to use a vapor barrier (plastic sheeting) over the concrete and cover that with sub-flooring (insulation covered with plywood) to prevent a moisture problem.