In a large mixing bowl, add the water and sourdough starter. Make sure the sourdough starter floats, that means it is active and ready. Mix well to dissolve the starter.
Add the flour and salt to the bowl and mix well until a shaggy dough forms. Cover with a damp kitchen towel. Perform a stretch and fold 30 minutes in and then another 30 minutes after that.
Let the dough rise at room temperature for 8-10 hours covered with a damp kitchen towel.
After the dough has risen, turn it out onto a lightly floured surface. Cut it in half and form the dough into two balls. Let them rest on the bench for 15 minutes.
Working with one dough ball at a time, stretch the dough into a pizza shape. Place the dough on your baking vessel. I like to use a cast iron skillet or pizza pan.
Preheat the oven to 450 degrees F. Place the dough into the cast iron skillet or baking pan. Bake for 10-15 minutes.
Remove the cast iron skillet from the oven and prepare your toppings.
Spread the sauce over the par-baked pizza dough. Make sure to evenly distribute the sauce over the dough.
Sprinkle with the mozzarella cheese and bake for another 5-10 minutes or until the cheese is bubbly and melted.