I have a gas water heater, years old, my pilot light will lite won't stay lite, main gas goes quickly as well

The heater was installed in my crawl space which happens to also be the lowest point in the house. This spring has brought a lot of rain with it and it collects at the base. This causes the pilot to shut off automatically. In the past it has been a sinch to relite it and move on wih life but this last time it has not cooperated. As I said the pilot light lites buut then after a short amount of time it sputters out. If I turn the main line on right away it sputters and goes out quickly. Help please, there is no hot water in my house and this means that I am going to be living with four stinky kids and a mad wife soon.