Why Xiaomi robot vacuum cleaner doesn’t do wet cleaning: diagnostics and repairs

Wet cleaning is a key feature of modern Xiaomi robot vacuum cleaners, but sometimes it stops working for no apparent reason: users are faced with the device driving around the room but not spraying water, leaving dry tracks or ignoring the washing command altogether, and 80% of the time the problem is solved by correctly identifying the source of the malfunction.

In this article, we will analyze all possible causes - from the banal lack of water in the tank to failures in the firmware, and also give step-by-step instructions for Mi Robot Mop 2 Pro, Viomi models. V3, Dreame D9 We will pay special attention to hidden settings in the Mi Home app, which often get lost after updates.

If your robot suddenly stopped washing floors, don’t rush to carry it to the service center. 9 out of 10 cases are not due to hardware failures, but software failures or operating errors. For example, many users do not know that in some Xiaomi models, the wet cleaning function automatically turns off if the battery level is below 20%. Or that the fabric nozzle needs to be washed at least 1 time every 2 weeks – otherwise the sensors will no longer recognize it as “clean”.

We have collected up-to-date data for 2026, including nuances for new models with the system. LDS 2.0 and laser sensors. And at the end of the article, you're waiting for you. FAQ The most common questions asked by the robot range from “why does the robot only clean half the room” to “can you use water instead of distilled water".

1. Testing the obvious: water, tank and nozzle

Start with the basics that are often overlooked, and in 30 percent of cases, the problem is that users just forget to add water or install the container incorrectly.

Open the water tank cover and check:

• 💧 The water level should be between the marks. MIN and MAX. If there is too little water, the pump will not pump it.
• 🔄 The position of the tank. Make sure it's tightly inserted before the click. V3 dreame D9 have contact sensors that block cleaning if the tank is set curve.
• 🧼 Clean nozzle. A fabric or microfibre nozzle should be wet, but not wet. If it is covered with dust or fat, the humidity sensor may not work properly.

Test the pump manually:

1. Take off the tank and the nozzle.
2. Pour the water to the maximum mark.
3. Enable wet cleaning mode through the Mi Home app.
4. If you put your ear on the body of the robot, you can hear the little buzzing sound of the pump, and if you don't, it's electronics or clogged.

⚠️ Note: Mi Robot Mop 2 Pro and Dreame F9 The pump may not turn on if the robot is standing on the carpet, and the system automatically blocks the water supply to keep the coating from getting wet.

2. Water supply system clog: how to clean

If there's water in the tank but it doesn't come to the nozzle, it's probably a clogged feeding path, and Xiaomi robots have water going through a few narrow channels that get clogged with lime plaque or dust over time.

Typical blockage sites:

• 🚰 Filter at the pump entrance (small net inside the tank).
• 🔧 The feed tube (thin hose from tank to nozzle).
• 💦 Spray holes in the nozzle.

Cleaning instructions:

1. Remove the water tank and rinse it under warm water. Use a toothpick to clean the filter hole.
2. Unplug the feed tube (most models have it on the latches) or rinse it with a 3% solution of vinegar if there is plaque.
3. Check the nozzle: if the nozzle holes are clogged, soak it in warm water for 10-15 minutes, then clean with a needle.

To remove lime plaque (relevant for regions with hard water):

1.Mix 1 liter of warm water + 2 tbsp. spoonfuls of citric acid.


2.Pour the solution into the tank and leave for 1 hour.




3. Turn on wet cleaning mode for 5 minutes, then drain the liquid.




4. wash the system with clean water 2-3 times.

⚠️ Warning: Never use aggressive detergents (such as Domestos or White) to wash, which destroy silicone seals and can incapacitate sensors.

3. Problems with the nozzle: wear, installation, sensors

A fabric or microfibre nozzle is a consumable that requires regular maintenance, and in 15 percent of cases, the robot does not wash the floor because of it.

Signs of a faulty nozzle:

• 🧺 The nozzle is too worn out (pouring, holes).
• 💧 It is excessively wet (the robot recognizes it as a leak and blocks the water supply).
• 🔍 The humidity sensor does not fix the nozzle (for example, if it is mounted curved).

How to check and replace the nozzle:

1. Remove the nozzle and inspect it for damage. If the fabric is worn, replace it (the original nozzles for Xiaomi are worth it). ~300-500 rubles).
2. Make sure the nozzle fits tightly to the base. - Viomi models V3 dreame D9 There are magnetic fixtures — if they don't work, the robot doesn't see the nozzle.
3. Check the humidity sensor (a small, circular sensor under the nozzle) and wipe it with a dry wipe, which sometimes gets dirty and gives false signals.

Care board:

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Wash the nozzle in the washing machine at 30°C without pressing, using liquid powder. Do not use underwear conditioner - it clogs the pores of the fabric and impairs water absorption.

4. Failures in firmware and application settings

If the mechanical part is fine, but the robot is still not washing, the problem may be the software part. After firmware updates or failures in the Mi Home, the wet cleaning settings often get confused.

What to check in the appendix:

• 📱 Cleaning mode: Some models have separate options for dry and wet cleaning. Make sure you choose Wet Washing or Comprehensive Cleaning.
• 🔧 Water supply intensity. You can set the settings to Low or Off.
• 🔄 If the robot is running on a timer, check if the settings are wrong (for example, wet cleaning can only be scheduled for certain days).

How to reset the settings to factory:

1. Open Mi Home → Choose your robot → Settings (⚙️).
2. Go to Additional Settings → Reset settings.
3. Select Reset Cleanup Settings (not a full reset!).
4. After restarting the robot, set up the wet cleaning again.

Firmware update:

Outdated firmware can cause pump failures to update the software:

1. Connect the robot to Wi-Fi.
2. In Mi Home, go to Device Settings → Firmware Update.
3. If the update is available, confirm the installation. Don't interrupt the process!

⚠️ Note: After updating the firmware to the version 3.5.8_003024 (In some models Xiaomi has a bug, because of which the robot ignores the command to wet cleaning, if the room has carpets with an area of more than 1 Solution: Turn off Auto Detect Carpet in Settings.

5. Failure of sensors and electronics

If all previous steps failed, the reason may lie in a hardware malfunction: in Xiaomi robots, several sensors and controllers are responsible for wet cleaning.

Key nodes that may fail:

• 💡 Water level sensor (detects the presence of liquid in the tank).
• 🔋 Water supply pump (can burn due to overload).
• 📶 Wet cleaning controller (controls spraying).

How to diagnose a breakdown:

1. Water level sensor: If the robot can't see water, even when the tank is full, it's likely that the sensor has broken. Check its contacts (they can oxidize). In the Mi Robot Mop 2 Pro models, the sensor is located at the bottom of the tank, and you can gently wipe it with alcohol.
2. Pump: If the wet cleaning is not activated, check its multimeter power supply (should be ~5V). If the pump is not working, the pump is burning.
3. Controller: If the pump buzzes but the water doesn't come in, the problem may be the control board, in which case you'll need to solder or replace the module.

Cost of repair in the service center:

⚠️ Note: If the Xiaomi robot is warranty, do not disassemble it yourself - this will void warranty obligations. mi.com/ru/support).

External factors: temperature, humidity, coating

Xiaomi robots are equipped with a protection system that blocks wet cleaning in adverse conditions, sometimes these security measures work falsely.

Factors that can block washing:

• ❄️ Low temperature (below) +5°C. Water can freeze in the system, so the robot refuses to spray it.
• 🌡️ High humidity (over 80%) Sensors perceive this as a risk of condensation inside the enclosure.
• 🧵 Type of coating: On carpets with a pile above 1 cm or laminate with a chamfer, the robot automatically switches to dry cleaning.

How to get around the restrictions:

• If the room is cold, move the robot to a warm room for 30 to 60 minutes before cleaning.
• To clean on the laminate or parquet, turn off the coating sensor in the settings (the option is Autodetermining the floor).
• If the robot "thinks" that the nozzle is too wet, dry it with a dryer in cold air mode.

Features for different coatings:

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If the robot refuses to wash the floor in the kitchen, check if it is standing next to a heat source (stove, oven), temperature sensors can falsely work and block wet cleaning.

7. Alternative solutions: if nothing helps

If you’ve tried everything, but the robot still doesn’t wash the floor, consider alternatives:

Interim measures:

• 🧹 Hand-cleaning with a nozzle. Take off the tank, wet the nozzle by hand and attach it back. The robot will drive around and wipe the floor dry, but with a wet cloth.
• 🔌 Using an external sprayer. Some users connect to the robot. USB-humidifier (sold on AliExpress) that sprays water before the nozzle.

Radical measures:

• 🔧 If the wet cleaning controller is burned, it is sometimes cheaper to buy a used board on an Avito than to repair an old one.
• 🆕 Upgrade to a new model: in Xiaomi robots from 2023-2026 (for example, DreameBot) X30 Ultra) uses a self-cleaning system of the nozzle, which breaks less frequently.

Where to look for parts:

• AliExpress - original and non-original pumps, sensors, nozzles.
• 4PDA — Firmware, repair schemes, advice from owners.
• Yandex.Market - service centers with home visits.

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Before buying parts, check their compatibility by the serial number of the robot (located on the bottom under the battery cover). For example, the pump from Mi Robot Mop 2 Pro is not suitable for Viomi. V3, though they look similar.

FAQ: Frequent questions about wet cleaning in Xiaomi robots