Too much salt DOES cause high blood pressure.
More Info: In salt sensitive individuals, consuming too much salt may be a factor in high blood pressure.
How Sodium Affects Blood Pressure
Some salt in the diet is necessary for healthy body maintenance. The body uses salt to maintain its fluid balance. When you intake too much sodium, the body's response it to retain water to dilute the excess sodium. The excess water increases blood volume causing the heart and blood vessels to have to work harder.
Some individuals are more sensitive to salt in their diets than others are. Referred to as ‘salt sensitive', these individuals see more effects of salt in their diets than ‘salt resistant' individuals. African Americans, the elderly, and people who suffer from diabetes are more sensitive to salt in their diets.
On average, Americans ingest far more than the recommended maximum intake of sodium per day. The American Heart Association recommends a daily sodium intake of no more than 1,500 milligrams. One teaspoon of salt contains 2,400 milligrams of sodium and is easily exceeded in the American diet through sources that you may not even be aware such as processed foods. ["Sodium (Salt or Sodium Chloride)." American Heart Association]