The answer to 'why is my water softener slow draining' is that a clogged or malfunctioning water softener is the most common cause of slow drainage. This can be due to a buildup of sediment, mineral deposits, or other debris in the softener tank or valves, which restricts the flow of water.
Some common symptoms of a slow-draining water softener include water taking longer to drain from the tank, the tank not fully emptying during a regeneration cycle, or the water flow from taps and appliances being reduced. To fix the issue, you may need to clean or service the water softener, or in some cases, replace worn-out components.