Whirlpool Dishwasher Error Code F13 — What It Means & How to Fix It

What Does This Error Mean?

The F13 error on your Whirlpool dishwasher indicates a problem with the water conductivity or softener salt sensor. This sensor measures the mineral content of the water to control the built-in water softener system. When the sensor malfunctions or reads an out-of-range value, F13 is displayed.

Affected Models

Whirlpool WDF series
Whirlpool WDT series
Whirlpool 6th Sense series
Most Whirlpool dishwashers with water softeners

Common Causes

The softener salt container is empty — there is no salt for the softener system
Salt residue or deposits have contaminated and clogged the conductivity sensor
The conductivity sensor has failed and needs replacement
Wiring damage between the sensor and control board
The water softener regeneration system has a mechanical fault

How to Fix It

Check the salt reservoir — it is usually located under the bottom rack near the drain. Refill it with dishwasher-specific regenerating salt if it is low or empty.

Use only dishwasher salt — do not use table salt or cooking salt, as they contain additives that can damage the softener.
Run a full wash cycle after refilling the salt. The machine needs to run a regeneration cycle before the sensor reads correctly.

It may take 1–2 complete cycles for the softener system to reset after refilling.
Inspect the salt reservoir cap and the area around it for salt deposits. Clean any crust with a damp cloth.

Salt residue can bridge across the sensor contacts and cause false readings.
If the salt is full and the error persists, the conductivity sensor may have a buildup of mineral deposits. Run a dishwasher cleaning cycle with a descaler tablet.

Heavy hard water areas may require monthly descaling to keep sensors clean.
If F13 persists after cleaning and descaling, contact a technician to test and replace the conductivity sensor.

This is not a user-replaceable part on most Whirlpool models.

When to Call a Professional

If refilling the salt and cleaning the sensor does not resolve F13, a technician should test the conductivity sensor directly. Sensor replacement typically costs $100–$180 including labor. The water softener system is integral to long-term dishwasher performance.

Frequently Asked Questions

What is the salt reservoir in a dishwasher for?

The salt reservoir feeds the dishwasher's built-in water softener. The softener removes calcium and magnesium from the water, which prevents limescale buildup on dishes and the machine. Without salt, the softener cannot work and hard water deposits will accumulate.

How often do I need to refill the dishwasher salt?

It depends on how often you use the machine and your local water hardness. In hard water areas with daily use, you may need to refill every 4–8 weeks. Most machines have a salt indicator light that tells you when to refill.

Can I use all-in-one dishwasher tablets instead of separate salt?

All-in-one tablets contain a water softener agent, but they are not as effective as dedicated salt in very hard water areas. For most hard water areas, using dedicated salt alongside any tablet type gives the best cleaning results and protects the machine.