Hi, This "phantom taste" is often a mystery to people and their doctors, However, if you not drinking enough fluid every day, you could be dehydrated and, therefore, your saliva might be saltier. This could also be the case if you drink a lot of caffeinated beverages. Caffeine is a diuretic, and can cause dehydration, as can alcoholic beverages.
The salt content of saliva may also change in response to medications - both prescription and over-the-counter. Postnasal drainage, caused by allergies for example, can cause a change in taste, as can an infection, such as sinusitis.
More unlikely possibilities include nutritional deficiencies, neurological disorders, including migraine, epilepsy and brain tumors, and endocrine disorders. Persistent salty taste is sometimes associated with leakage of cerebrospinal fluid. Again, the likelihood of your taste problem being traced to one of these causes is remote and rarely would a change in taste be the only symptom.