Water Dripping From Bathroom Fan? 5 reasons why.

In general, water dripping from a bathroom fan is caused by water condensation, due to lack of insulation on the exhaust hose or duct, lack of proper airflow due to vent blockage, or an improperly installed bathroom fan, to name a few.

Whenever you find water dripping from an electrical appliance, such as your bathroom fan, needless to say, it tends to make one nervous. But, depending on the reason behind the drip, it might be an easy thing to fix.

Most homes built within the last three decades have an exhaust fan in the bathroom. The primary function of a bathroom fan is to remove all the moisture that accumulates in the bathroom following a shower or bath. However, a bathroom fan may occasionally drip water, and this can be caused by several different factors.

when You Have water dripping from A Bathroom fan

Fortunately, there are a few actions that can be taken to prevent the situation from becoming too severe.

Any bathroom that does not have a window that can be opened to provide ventilation is required to have a bathroom vent fan installed according to the IRC (International Residential Code) and applicable municipal construction laws. 

Depending on the jurisdiction, a fan may be required even if there are windows present.

Check for inadequate Insulation.

The insulation’s primary function is to separate the warm air that is vented out of the bathroom from the colder air that is found in the attic during the winter. 

Note: We earn a small commission on purchases, at no additional cost to you.

Attic view of exhaust fan

This will prevent condensation from forming.

If the weather is cold outside, your air ducts are as well. As warm air from inside your home begins to pass through the vent duct, condensation will form on the walls of the duct. Therefore, if you see water dripping from your exhaust fan after you have bathed or showered, it is likely that your insulation (or rather, lack thereof) is the source of your problem.

Not only the insulation around the ductwork should be considered, but the insulation in your attic might also be insufficient as well. In fact, it has been the practice of many contractors to leave the ducts themselves uninsulated because they know the attic insulation will be covering them.

Have a Question? Ask HVAC Technician

Click here to use the chatbox to speak with one of our technicians.
No in-home service calls. No appointments.

That’s just fine as long as the attic insulation remains in place. However, blown-in insulation will settle over time and eventually could end up no longer adequately covering your ducting. It would be good to take a peek.

Solution: Replace your existing insulation with more durable and better-fitting insulation materials, or add blown-in insulation, as needed. Perhaps the insulation has slipped down the ventilation duct over time, leaving the top portion of the ventilation duct unprotected. Maybe it just needs to be re-secured.

To guarantee that the insulation is properly installed, a certain level of competence is required. If you’re unsure of your own capabilities, have someone with experience take care of it. Since this is in the attic, and out of sight, you want to be sure it is a permanent and proper fix, to avoid recurring issues down the road.

Check for proper Bathroom Fan airflow.

When a bathroom fan’s exhaust vent is obstructed or lacks sufficient airflow to the outside, condensation can accumulate rapidly, potentially leading to dripping issues. To ensure your fan is operating effectively, conduct a simple test using toilet paper.

Turn on the fan, and hold a single piece of toilet paper near the grille. If the fan is functioning properly, it should draw the toilet paper towards it, causing it to stick to the grille. If this doesn’t happen, the fan might be generating noise, but isn’t creating enough airflow through the duct to remove the humidity from the air.

Suction test for fan

Identify The cause of improper Fan airflow

If you find that there is inadequate airflow, the next step is to figure out what’s causing this.

#1 Dirty Fan Grille

Remove the grille and look it over for plugged holes or slots. Most grilles are easily removed simply by grabbing the edges pulling straight down from the ceiling. They typically have two spring arms that hold the grille to the ceiling by way of tension.

Once the grille is lowered a few inches (until it catches), you will likely have to pinch each arm together to pull it out of the slot in the fan housing. There are various other methods of attachment also, depending on the model of the fan.

#2 Dirty Fan housing

With the grille removed, check inside the fan housing to see if there is excess buildup of lint and dust around the fan blades and motor. These areas can get very dirty after just a few years, if not cleaned regularly.

Use a vacuum to clean inside the housing. Use a crevice tool to get into the small spaces. This will also extend the life of the fan, as debris buildup can cause imbalance and premature failure of the motor and bearings.

#3 Fan Duct blockage

If your grille, fan blades, and motor are clean, and you still have low or no airflow, it’s time to check the duct for blockage. Sometimes, using a shop vacuum on reverse (blow) will push the debris out. Other times, it requires a duct snake to dislodge and remove the offending blockage.

Note: We earn a small commission on purchases, at no additional cost to you.

But before you fire up the shop vac, take a look outside. There are three main places the ducting may expel the air: at the side wall of your house, under the eave, or through the roof.

types of fan vents

You may have to do a little searching to find the spot where your ducting exhausts the air to the outside. Turn the fan on before you head out. You might be able to see the louvers or flap moving at the exit location. With a ladder, you also may be able to hear the fan motor or feel the air coming out.

If the vent flap or screen is damaged or missing, it is possible that rodents or birds have made a nest in your duct. This is a common cause of vent duct blockage, especially in rural areas.

bird nest in vent

#4 Crushed or kinked duct

Another possibility, especially if your duct runs through the attic, is that the duct may be kinked or crushed. Anyone walking or crawling through the attic could have inadvertently stepped on kneeled on the duct, causing a bottleneck in the run.

If that’s the case, usually replacing the damaged section is the only viable option.

Clean A Dirty Bathroom Exhaust Fan

Having an extremely dirty bathroom fan is similar to having a blocked or damaged bathroom vent and can significantly hinder airflow and may be a contributing factor to the condensation. In severe situations, it can even create a fire hazard if not dealt with properly.

The bathroom fan cover often includes a large number of small holes or slots, which may become blocked with dust. If the vent holes are obstructed, the bathroom fan may only be sucking out a small amount of the total volume of moist bathroom air.

Cleaning the fan should be a regular practice. It’s easy to forget about it, and almost none of us do it. But it could easily save you money and headache in the long run if you can remember to take a few minutes each year and vacuum out the fan housing.

dust buildup can cause water dripping from bathroom fan

Replace the exhaust fan if necessary.

If everything appears to be in working order, you should pay close attention to the bathroom fan itself. It is possible that the fan will not be able to remove all of the moisture due to its capacity.

The capacity may be too low in comparison to the size of the bathroom. Or the duct run may be too long or windy for an under-powered fan. If you have a big number of family members who like taking hot showers regularly, a strong exhaust fan will be required to do the job efficiently.

The majority of bathroom fans have a lifespan of between ten and fifteen years. When it comes to removing moisture out of the bathroom, older and slower ventilation fans are less effective than their more modern counterparts. Replacement may be required to ensure that your bathroom is free of moisture. 

The exhaust fan must be powerful enough to provide fresh air to the bathroom every 7 1/2 minutes or eight times an hour. This is the accepted industry practice.

Fan location Can Be Modified

It’s possible the location of the fan isn’t optimal, though this is less likely the reason for condensation buildup. Still, it’s something to consider. The bathroom fan should be located in the bathroom, in the area that is subjected to the greatest amount of moisture. In most cases, this refers to a location near the bathtub or shower.

The aim of the exhaust fan is largely to remove wet, humid air that might contribute to mold development or moisture damage in the bathroom. So, the closer to the source, the better.

While such a location is ideal, a fan can be placed anywhere in the bathroom as long as there are no obstacles which would hinder the bulk of the moisture from reaching the fan. If you have both a tub and shower in the same bathroom, a single fan is all that is necessary. Optimally, that fan would be placed between the two fixtures.

Though it is permissible to install the fan directly over the bathtub or shower (with GFCI protection), any adjacent location near the bathing area will suffice.

Run the fan regularly.

Keep the bathroom fan going while you take a hot shower. Continue to leave it running for at least 10 to 15 minutes after you have finished your shower.  I have my bath exhaust fans on timer switches. That way, I can push the 30 or 60-minute button, take a shower, and walk away, letting the fan continue to run until it times out.

Note: We earn a small commission on purchases, at no additional cost to you.

These timers are relatively inexpensive, easy to install for a DIY person, and are very convenient. I recommend them to my customers often and they are always grateful for the idea.

wall timer switch for fan

This will ensure that all of the moisture is removed from your bathroom as soon as possible. There will be no moisture build-up, which will prevent further drips from occurring. With a timer, you won’t have to worry about the fan getting left on for hours afterward.

Another convenient method is to install a humidity detecting bathroom fan to automatically remove and maintain a regulated moisture level in the bathroom. These are a bit pricier, but are fully automatic.

Note: We earn a small commission on purchases, at no additional cost to you.

Install a dehumidifier (if needed)

The climate in which you live may be an added factor to your problem. Install as many dehumidifiers as needed around your home to ensure that you have a level of comfort even on the warmest days of the year, when the humidity is at its highest.

Considering that a single dehumidifier can only cover so much space, you may want to install several of them to guarantee that your entire home is protected from too much moisture. Or, invest in an HVAC system with an integrated dehumidifying function.

Related: Dehumidifiers in Crawlspaces

dehumidifier removes moisture from room

Roof vent covers May need to be replaced.

As mentioned above, if your bath exhausts through the roof, you should check the roof vent cover (louver) to make sure it is not damaged. Nine times out of ten, if the leak only happens during windy and wet conditions, the cover is most likely to be the source of the problem. 

Note: We earn a small commission on purchases, at no additional cost to you.

Heavy winds, flying debris, and other outside factors can all cause damage to the louver at different times of the year. Because it is located on your roof, the cover is in an area of your property that is subjected to the most adverse effects of nature.

If you discover a faulty or damaged vent cover on your roof, this indicates that water can travel through it. To ensure that the roof vent cover is not damaged, you should check it carefully before proceeding. It is possible that the cover has not been damaged, but rather that it has been fitted improperly, resulting in water seeping from the outside of the vent duct opening. 

Have a professional replace the item that has been damaged if you cannot do it yourself.


Moisture and condensation can lead to some real problems around the home and can impact the overall health of the occupants. Areas such as kitchens and bathrooms that generate heat from the use of hot water, as well as stoves, must be ventilated properly.

Routine checks on your systems can go a long way toward keeping you problem-free. Though some of these repairs will come at an up-front price, the lack of maintenance almost always costs more in the long run.