House is 40 years old. A Bilco door is at the rear of the house close to the chimney structure outside. The door is rusted and tiny holes can be seen from the basement out. With heavy rain water gets inside. The previous owner built a low deck (16x16) so the Bilco door is sitting inside the structure.

There is French drain in the basement but not at the bottom of the stairs(Bilco). When the water gets in, it goes around the chimney base to the drain but the water also flows forward under the furnace to other places.

Before the last heavy rain, I placed a Tarp over the door, but the same amount of water got inside. I pulled up the deck boards and the deck posts were resting on cinder blocks. The blocks were sitting in sunken dirt. The water is entering the basement from the sides of the Bilco door at the bottom of the steps at the rate of a faucet.

I know I have to replace the Bilco door and maybe have to fix the cement support.

My question is what are the options to prevent the water from entering? please give a brief step so when I call the contractors in for estimate I have a better idea to ask appropriate questions