THE TEST: We boiled a pound each of dry spaghetti (sodium-free) in 4 quarts of water containing varying amounts of salt.
THE RESULTS: (per 6 ounces cooked pasta); 1 teaspoon salt (2,360mg sodium): 75mg sodium; 1 tablespoon salt (7,080mg sodium): 253mg sodium; 2 tablespoons salt (14,160mg sodium): 446mg sodium; ¼ cup salt (28,319mg sodium): 896mg sodium
Bottom line: It's not that pasta soaks up salt like a sponge: Only 3% was absorbed into each serving of pasta. But 3% of the sodium in ¼ cup is 896mg—nearly 40% of your 2,300mg daily limit. So reduce (don't eliminate) the salt in the water; save it for the sauce.