Is It Ok To Leave Water In A Humidifier?

Yes, it is OK to leave water in a humidifier. Most modern models are designed to keep the water safe until you need to refill them again. The internal components of the humidifiers can help prevent bacteria and mould growth by keeping any standing water clean and fresh. Many have an antibacterial coating on the tank that helps protect against harmful organisms. If you own an older model humidifier, consider replacing it with a newer one that has these protective features.

Is It Ok To Leave Water In A Humidifier?

Humidifiers can be an effective way to reduce dryness in the home or office, but it’s important to ensure that you maintain your humidifier properly. The question of whether it is safe to leave water in a humidifier when not in use is one that many people have.

The primary concern when it comes to leaving water in the humidifier is that standing water can act as an incubator for bacteria and mould. Microscopic organisms, such as bacteria and mould spores, thrive in moist environments and can cause respiratory illnesses when inhaled. Therefore, cleaning and disinfecting the humidifier on a regular basis is essential to maintain your health.

What Can A Humidifier Do?

Humidifiers are machines that add moisture to the air in a room. They can be used to increase humidity levels in dry climates, reduce dust, reduce static electricity, and even help address certain health concerns such as asthma or allergies. The humidity level of an indoor environment affects us all, so it’s important to know how a humidifier can help.

When it comes to adding moisture, humidifiers work by releasing tiny water droplets into the air, which eventually evaporate and increase humidity levels. Humidifiers come in many varieties, such as cool mist or warm mist units, and each type has its own benefits. Few of them are following:

  • Better sleep: Humidifiers make the air in a room easier to breathe. This can help people sleep better by improving respiratory comfort.
  • Relieve cold symptoms: By adding humidity to the air, a humidifier may also help relieve cold and flu-like symptoms such as congestion, coughing, and sore throats.
  • Allergy relief: humidifiers can help reduce the symptoms of allergies by adding moisture to the air. However, leaving water in a humidifier for an extended period of time can cause bacteria and mold growth in the reservoir. This bacteria and mold can then be released into the air, exacerbating allergy symptoms even further.

What Type of Water Should be Used in a Humidifier?

When it comes to humidifiers, the type of water used can be just as important as how often you are emptying and refilling it. Generally speaking, tap water is acceptable for use in humidifiers, but distilled or demineralized water is highly recommended. Hard water contains calcium and magnesium ions which can build up inside the tank and cause mineral deposits. These minerals can also be released into the air, creating an unpleasant odor and potentially damaging your walls or furniture. Additionally, distilled water lacks some of the bacteria found in tap water, making it a much better choice for your humidifier.

How Often Should I Change The Water In My Humidifier?

It is important to change the water in your humidifier frequently to prevent bacteria, mold, and other contaminants from building up. Depending on what type of humidifier you have, it is usually recommended that you change the water daily or every other day. If you are using a cool mist humidifier, be sure to empty and refill it with fresh water at least once a week. If you are using a warm mist humidifier, it is generally recommended that you clean and refill the tank with fresh water twice a week to prevent buildup of minerals in the tank.

When Should You NOT Leave Water In A Humidifier?

If you’re using a cool mist humidifier, it’s generally safe to leave the water in the tank between uses. However, keeping water in your humidifier for too long can be detrimental to its lifespan, and may also lead to bacteria growth. It’s best to empty and clean out the tank after each use (or at least every few days).

For warm mist humidifiers, it’s generally not safe to leave the water in between uses. It should be emptied out and refilled with fresh water each time that you use it. With warm mist humidifiers, it is important to keep a tight lid on the tank when not in use as this helps prevent bacteria growth due to the presence of heat.

Can You Leave Distilled Water In A Humidifier?

Yes, it is safe to leave distilled water in the humidifier tank. The minerals found in tap water can build up inside the humidifier over time and cause a white dust to be spread throughout your home when you use it. You can leave distilled water for up to one year if stored properly.

Can You Leave Reverse Osmosis Water In A Humidifier?

Yes, you can leave reverse osmosis water in a humidifier for an extended period of time. This is because reverse osmosis water has already been filtered to remove heavy metals, chlorine and other impurities that could build up, clog or damage your device over time. It also eliminates the need to constantly change out the water regularly as you would with regular tap or distilled water. It can be stored up to six month. make sure to store the humidifier properly.

Can You Leave Zerowater In A Humidifier?

Yes, Zero water can be leave in a humidifier up to six months. It is not recommended to leave water in the reservoir of a humidifier for longer than six months due to bacteria, mold, and mineral build up. If you are using ZeroWater in your humidifier, it is best to clean and refill the reservoir every 6 months for optimal performance. You must remove the water when it is no more needed.

Can You Leave Brita Water In A Humidifier?

Yes, it is ok to leave Brita water in a humidifier. You can leave it for only 5-7 days. When the humidifier is not in use remove the water as soon as possible. Brita water is safe to be used in humidifiers as it does not contain sediment or other particles that can clog the machine.

Can You Leave Tap Water In A Humidifier?

Yes, you can leave tap water in the tank of your humidifier for short periods of time. The time can be different according to the quality f tap water.

Test Water Before Using In Humidifier

  • Iron: You should test the iron level of water before using it in a humidifier. Iron can be harmful to the device, so always check the iron content of your water source before refilling your humidifier.
  • Total dissolve solids: The amount of minerals in the water being used is also a factor when determining how long to leave the water inside your humidifier. If there are high levels of Total Dissolved Solids (TDS) in the water, it’s best to empty and clean your humidifier more frequently as they can settle on surfaces inside the machine and cause mildew to grow. There are products available that can help reduce the amount of TDS in your water, such as filters and demineralization cartridges.
  • Hardness: The level of hardness in the water that you use for your humidifier is important. If you are using hard water, it can lead to scale buildup, which will reduce the effectiveness of your humidifier. Therefore, if you are leaving water in a humidifier for an extended period of time, it’s best to use distilled or softened water.

Common Mistakes People Make When Using A Humidifier

Ignoring Humidity Levels in Your Home: Setting a humidifier without properly monitoring the humidity levels in your home can lead to condensation and mold growth on walls, floors, and furniture. It is important to use a hygrometer (a device used to measure humidity) to make sure that the relative humidity level stays between 40-60%.

Letting Humidity Levels Rise Too High: If you leave water in a humidifier for too long, the humidity levels in your home can rise to uncomfortable levels. This can cause condensation on windows and walls, as well as mold growth in certain areas of the house. It is important to monitor the humidity levels with a hygrometer or other means and adjust accordingly.

Neglecting to Clean the Humidifier Often Enough: It is important to clean your humidifier on a regular basis. If you leave water in the unit for too long, bacteria and mold can grow, which may lead to health problems if you are exposed to the air coming out of the humidifier. Additionally, leaving water in the unit can damage it over time by leading to mineral build-up, which is much harder to clean out.

Essential Tips To Maintain Your Humidifier

Wash the water tank: Empty the water tank and rinse it with cold water to remove any residues. Always use distilled or filtered water in your humidifier, as this will help prevent buildup of minerals inside the unit which can affect its performance.

Rinse the filter regularly: Depending on the type of humidifier you have, it is important to clean and rinse the filter regularly. Otherwise, bacteria can grow and thrive in standing water, making any humidity released from your device unsafe for breathing.

Wipe down the frame regularly: Cleaning your humidifier regularly is important to ensure a healthy environment. Always make sure to wipe down the frame of your humidifier with a cleaning solution after use, as well as any other parts that are exposed to moisture. This will help prevent the growth of mold and bacteria in the machine.

How To Clean Humidifier?

Step 1: Unplug the humidifier from its power source before cleaning to prevent electrocution.

Step 2: Empty any remaining water, then rinse out the tank with hot, soapy water and a cloth or sponge to remove dirt and bacteria buildup.

Step 3: Clean other parts of the unit, such as the wick filter, with a mild detergent and water solution. Rinse off completely before returning to the unit.

Step 4: Wipe down all surfaces of the humidifier with a damp cloth to remove dust and debris.

Step 5: Dry the interior of the humidifier thoroughly using an absorbent cloth or paper towel.

Step 6: Refill the tank with fresh, clean water and plug the humidifier back in to use.


What liquids can you put in a humidifier?

The type of liquid used in a humidifier depends on the model and its instructions. Generally, water is preferred for use in a humidifier because other types of fluid may damage the device or cause it to malfunction. It is also important to check that any cleaners recommended by the manufacturer are safe to use with your specific model.

Can you use bottled spring water in a humidifier?

Yes, it is safe to use bottled spring water in most humidifiers. However, distilled or demineralized water will minimize the risk of buildup caused by minerals in the water.

Can I humidify a room with a bowl of water?

No, a bowl of water isn’t an effective way to humidify a room. Humidity levels in a room can be increased with the use of a humidifier. Humidifiers vary in design and effectiveness but their purpose is to add water molecules into the air in order to increase the humidity level.

Why cant you drink distilled water?

You cannot drink distilled water because it lacks essential minerals and electrolytes, such as calcium and magnesium, that are necessary for good health. It is also stripped of the natural compounds that give other types of water their taste.

How dangerous are mould spores in a humidifier?

Mould spores can be dangerous and cause health problems when released into the air. These can be dangerous for people with asthma and allergies, as they may worsen symptoms or lead to other respiratory illnesses.


Ultimately, it is not recommended to leave water in a humidifier when the device is not in use. When left untreated and sitting, the water can become a breeding ground for bacteria and mold. The warmer temperature of a humid environment like that provided by a humidifier also helps these organisms to reproduce quickly. To avoid this risk, always empty and clean the humidifier after use and store it in a dry area away from direct sunlight. Additionally, make sure to follow any specific instructions provided by the manufacturer with regard to care and maintenance of your device. This will help ensure that your humidifier is running optimally and keeping the air quality in your home healthy for you and your family!

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