A washing machine relies on precise internal communication to perform each stage of the cycle correctly. One of the most critical components responsible for that accuracy is the water level detection system. When your washer stops recognizing how much water is inside the drum, the entire wash cycle becomes unreliable. You may notice the machine overfilling, underfilling, stopping mid-cycle, refusing to start, or showing unexplained error codes. All these symptoms often point to a single issue: a malfunctioning pressure sensor or a kinked pressure hose. Understanding how these components work and what happens when something disrupts them can help you act quickly, prevent damage, and avoid costly repairs in the future.

How the Washer Detects Water Level

Inside every modern washer, there is a pressure sensor (sometimes called a water level switch) that communicates with the control board. Its role is simple but essential: it measures the air pressure inside a small hose that connects to the bottom of the tub. As the water level rises, the air pressure increases, and the sensor interprets this change to determine how much water is present. This information allows the washer to fill correctly, maintain balance, use the right settings for the cycle, and prevent overflow. When the sensor or the hose malfunctions, the entire logic of the machine is disrupted.

Signs the Washer Is Not Detecting the Water Level Correctly

Several symptoms may appear, depending on the nature of the malfunction:

• The washer fills with too much or too little water
• The machine refuses to start a cycle
• The cycle stops unexpectedly
• Water continues running even when the drum is full
• The washer drains immediately after filling
• Repeated error codes related to water level or pressure
• Clothing comes out poorly washed because the water level was incorrect 

These issues rarely resolve themselves, and the longer you ignore them, the higher the risk of water damage or motor strain.

Common Cause 1: A Malfunctioning Pressure Sensor

Pressure sensors can fail due to age, moisture damage, electrical faults, or internal corrosion. When this happens, the sensor sends incorrect signals to the control board. For example:

• It may think the drum is empty when it is actually full
• It may detect overfilling that isn’t happening
• It may fail to switch between water levels
• It may misread pressure changes and cause cycle interruptions 

Because the sensor interacts directly with the control module, even a minor malfunction can lead to significant behavior changes in the machine. Replacing or repairing the pressure sensor requires accurate diagnostics because other parts of the washer may show similar symptoms when failing. A professional technician can test the sensor, identify electrical issues, and replace the component with a compatible model.

Common Cause 2: A Kinked or Blocked Pressure Hose

In many cases, the sensor itself is fine, but the hose connected to it is not. The pressure hose can become kinked, twisted, clogged with detergent residue, or clogged with lint. When airflow inside the hose is restricted, the sensor cannot read the pressure correctly. A kinked hose may cause:

• Overflow due to inaccurate readings
• Underfilling because pressure does not rise correctly
• Sudden draining because the sensor thinks the drum is too full
• Intermittent errors that appear only during certain cycles 

Blockages inside the hose act similarly. Built-up residue can trap pressure, giving the sensor false readings. This problem is especially common in older machines or washers frequently used with heavy detergents. Straightening or cleaning the hose may help, but in many cases the blockage is deep inside or the hose has become brittle and needs replacement.

Why You Should Not Ignore These Issues

Problems with water level detection are more serious than they appear. Incorrect water levels can cause the machine to overwork, strain the motor, waste water, and damage internal parts. Ignoring the problem may lead to:

• Flooding
• Drum imbalance
• Premature wear of the motor
• Failure of the control board
• Mold growth from leftover water
• Safety hazards due to electrical moisture exposure 

A professional inspection ensures that all components are functioning as intended and that no hidden issues are developing inside the machine.

Professional Repair Makes the Difference

Diagnosing a water level detection issue requires experience and specialized tools. Technicians test the sensor electronically, inspect the hose for blockages, evaluate the control board, and check all related components. A proper diagnosis saves time, avoids unnecessary part replacements, and restores the washer’s performance quickly. If your washer struggles to detect the correct water level or shows any symptoms listed above, professional assistance is the safest and most reliable solution. To restore your washer’s proper operation, contact San Diego Appliance Repair Service. Our specialists provide fast diagnostics and effective repairs to keep your appliance working smoothly.   Contact us (619) 719-5005   [email protected]