On many toilets, there's a jet (hole) located in the front portion of the lowest part. When you flush, a jet of water shoots backwards horizontally and gets the water flowing quickly. If you have hard water, lime deposits can plug that hole up completely.
If you have a septic tank and want to check to see if it needs pumping, you'll have to remove the cover over the inspection hole, so that means digging time. To find the tank, take a steel rod and poke down into the soil, usually there isn't much more than about a foot of dirt over it. After you find the hole, take a long, thin board or the like, nail another piece of wood or Masonite approximately 6X6 or 8X8 inches flat onto the end and slowly lower it down into the hold. On the top will be foam, then water and at the bottom, you should feel some resistance as the flat board makes contact with the solids (they'll be mushy). After you feel the solids, make note of how much of the pole is exposed, then push the board down all the way to the bottom and again check the pole length. If the solids are more than around 25% of the tank depth, it needs to be pumped.
Baltimore Sewer Service