A clogged drain hose, faulty water softener rotor valve or leaking rotor valve seals can cause salty output water from the water softener.
A clogged drain hose can prevent brine water from being flushed from the resin filter during regeneration, causing salty water. Clear the drain hose if it's clogged.
A bad rotor valve won't direct water through the softener properly and can cause salty output water. Use the diagnostic test in the owner's manual to check the operation of the rotor. Replace the rotor valve if it won't move when the valve motor runs.
If the drain line is clear and the rotor valve moves properly in the diagnostic test, then leaking seals in the rotor valve are likely causing salty output water. Examine the rotor valve seals and replace any damaged seals.