To check toilets, put a few drops of food coloring in the tank. Do not flush. If the color appears in the toilet bowl, there is a leak. Have leaks repaired immediately. Your flapper, flush valve or valve Seat may need to be cleaned or replaced.
Parts are inexpensive and fairly simple to install.
Check under all sinks, behind your washing machine and in the basement for suspicious looking wet areas. These leaks not only waste water, they could be damaging your cabinetry, walls, floors or ceilings. Pipe repairs are best left up to your plumber. Insulate hot water pipes . Water is wasted if you turn on hot water tap and wait for hot water to come up.