Kia Sportage petrol leak

Petrol leaking from below the car near driver s side rear door,does not seem to be coming from the top of the tank but somewhere near the bottom although difficult to see actual location.Is this likely to be the tank itself or the metal fuel pipes. How are the pipes connected to the tank and is it possible to repair it myself if it is the pipes?Is this a common problem with this type of car, it is much worse when the engine is running and it is getting very expensive, thank you. I have resisted the temptation to light a match for a better view|