Water In your Dryer Vent? How To Easily Prevent And Fix It7 min read

A typical dryer releases between one and two gallons of water per load. Sometimes the dryer vent experiences a buildup of water and this can cause significant issues with the efficiency of the dryer and in your home. 

Water in a dryer vent is caused by a blocked vent duct (usually lint), condensation, or a duct that’s too long. Homeowners should clear their dryer vents regularly, ensure that the vent is insulated in cooler rooms, and consider utilizing a booster fan if the duct is longer than 10 feet. 

Through firsthand experience and lots of research, I’ve written a step-by-step article on how exactly you can prevent a water buildup in your dryer vent. I start with the most common reasons and write systematically through the easiest and quickest fixes to these issues. 

This article has been expert reviewed and fact-checked by Andy Fulenchek, a professional appliance repairman with over 10 years experience, and owner of Grace Appliance.

Why Is There Water in Your Dryer Vent? 4 common problems and solutions

Water in a dryer vent is not an uncommon problem to have. When moisture, blockages, and other issues are present, it can be easy for your vent to experience a buildup of water. 

The most common reasons causing water buildup in your vent are a blocked dryer vent pipe, condensation, and improper venting. 

Common SignsCause Of Water In Dryer VentHow To Fix Water In Dryer Vent
Water In Dryer Vent, Longer Drying Times, Hot Exterior Of Dryer, Lint BuildupDirt Or Blockage In VentClear Dryer Vent At Home Or Through Help Of A Professional
Duct Goes Through Basement, Vent Is Leaking Water, Air From Exhaust is Warm Not HotCondensation On VentInsulate The Dryer Vent
Vent Is Longer Than 10 Feet, Extended Drying Times, Lint BuildupDryer Vent Duct Is Too LongUse An Inline Dryer Fan

1. Rainwater or lint

Before diving into the most common reasons for water accumulation in your dryer duct, I’ll run through two quick and easy checks you should perform right away.

Firstly, make sure that the water in your vent duct isn’t a result of rainwater seeping in from the outside. While it may seem obvious, damaged or permanently open flappers on the exterior vent cover can provide an entry point for water and other obstructions to enter your vent.

Secondly, clear out the lint tray inside your dryer! This step is crucial as lint accumulation can cause problems with both drying clothes and the functioning of the exhaust/fan system in your dryer. 

Lint coming out of dryer vent

In fact, lint is the primary culprit responsible for a wide range of issues experienced with dryers.

2. a blockage in your dryer vent

The most common reason a dryer vent has a water problem is due to a dirty or blocked vent. If you do not frequently clean your dryer vent, lint will build up and cause a blockage.

During the drying process, the dryer exhausts lint, and air (and moisture from clothes) out of your vent hose. The lint forms a blockage within the vent and this means the moisture gets caught in the vent, causing wet lint and water in your vent pipe. 

Over a gallon of water is exhausted from every load and if it cannot escape out the outside vent, it’ll cause problems.

Note: Lint is a highly flammable material and can cause fires, so it’s crucial to remove lint from the dryer vent as much as possible. 

Here are some common signs that you have a blocked dryer vent: 

  1. Longer drying times: The blockage prevents the hot, moist air from escaping your dryer efficiently, causing the drying process to be less effective.
  2. Hot exterior of the dryer: When the vent is partially blocked, the heat produced by the dryer has nowhere to go and can build up inside the appliance. 
  3. Excessive lint buildup: If you find an excessive amount of lint collecting around the dryer or in the lint trap, it may indicate a partially blocked vent. 

3 ways to easily clear a blockage within your dryer vent

You have two options for clearing out your dryer vent: hire a professional or do it yourself at home. A professional will charge around $150 and I’ll explain here how to do it at home: 

The first option is to use a dryer clean-out kit like this one (on Amazon). This is basically a long flexible brush that you can attach to your power drill or vacuum cleaner, enabling you to easily clean the entire length of your vent. This is an easy, cheap DIY way to clear your dryer ducting.  

Do NOT put the drill in reverse when removing the brush from the wall. you’ll see that the sections of the kit screw together and if you reverse the direction of your drill, you will lodge the cleaning rod INSIDE your wall (…) I have heard nightmare stories from other technicians that involved cutting out drywall to access the stuck rod/brush..

Andy Fulenchek

The second option is to use a leaf blower! Remove the critter screen first (on the outside) and blow the leaf blower from your laundry room. Remember to blow from the inside out, otherwise, you’ll create a huge mess! This will blow out any excess lint or blockages. Hopefully, you don’t find any dead mice in there…!

Using Leaf Blower to clear dryer vent

Note: you’ll need to be careful if your dryer vent hose is the flexible aluminum type, especially if it’s old. The power of a leaf blower could damage it. 

The third option is to replace the vent ducting entirely. Especially if you have the flexible aluminum type, you could take this as an opportunity to upgrade and replace it. In most cases, to be within code a vent needs to be a rigid pipe.

The shorter the better, smooth is good, and a minimum of 4″ wirde is needed. 4″ wide is the standard for residential.

Andy Fulenchek

It can be challenging to free the vent entirely of lint. Yet, removing as much as possible will reduce fire hazards and minimize blockages. If you forget to clean the vent, it could become blocked, which will restrict the airflow of the machine. A lack of airflow will result in the water not being able to escape. 

The National Fire Protection Association recommends cleaning your dryer vent every 12 months. If you have a pet, like me, vents can clog quicker so I’d recommend more regular cleaning as dryer fires are the number 2 cause of house fires (directly behind open flames).

I have seen 1/2″inch layer of lint sitting on top of a Samsung heating element canister. In this case, the vent hose on the inside of the dryer had become dislodged and the vent leading out of the dryer was not even hooked up. It was blowing lint directly INSIDE the cabinet of the dryer! Literally, all it would have taken was a spark or a peice of lint catching fire to set it all ablaze.

Andy Fulenchek

3. Condensation in your dryer vent

Any dryer duct that runs through a cold space will experience a change in air temperature. The dryer produces warm, moist air that condenses on the cool vent pipe causing condensation. This is particularly true where the dryer vent runs through cooler areas such as the basement or attic, or where the home is air-conditioned. 

Dryer Vent In Basement

I also wrote an article on how to effectively vent a dryer in a basement you might find useful. 

Aside from noticing water pooling in cooler areas, another way to check for condensation is to feel the temperature at the exhaust vent whilst the dryer is running. The air should be very warm bordering on hot. Typical cycling temperatures at the exterior vent will cycle up and down between 120-155F.

Where the exhaust air is only slightly warm, it’s an indicator that the vent is experiencing a drop in temperature before reaching the exterior of the property. 

When you’re experiencing condensation, you’ll also probably notice that your dryer vent is the flexible type and lacks any sort of insulation. The good news is that this is a relatively easy fix, and next, I’ll take you through some pointers to get it fixed.

How to eliminate condensation in your dryer vent

1. Insulate the entire length of the vent

Your dryer vent should be well-insulated to avoid temperature issues. If your vent is not insulated, it can cause moisture issues when the weather is cold. 

It is best to insulate the entirety of the vent to make it as efficient and safe as possible, using insulation like this (on Amazon). The best type of duct to use is the round 4-inch metal duct, and only use flexible aluminum ductwork between the round metal and the dryer itself. 

Note: Verify that the insulation is fire resistant and appropriately heat rated, as sections of a dryer vent can approach 200F+ inside the dryer. I have personally seen insulation sold in Home Depot that is NOT heat-rated this highly, so be vigilant.

Dryer Vent Insulation

Aside from Amazon, you can also buy 4-inch duct insulation from your local hardware store – it’s normally sold in 50-foot chunks and you can cut it to the desired length.  

2. ensure correct duct installation

Where your ventilation duct moves horizontally or upwards, you’ll encourage condensation buildup water to sit and pool rather than drain out of your vent.  

It’s best practice to install your vent pipe with a slight downward slope, which also minimizes the chances of leakage from duct joints. This will let the water drain outside rather than onto your basement floor! Always ensure there are no P-trap-type bends within your duct where water can pool (or lint, which is a fire hazard). 

Note: using 10-foot sections of solid ductwork will minimize the number of joints needing sealing. 

Make sure not to use screws to attach the sections of the pipes as the protruding screw in the vent will be a spot that lint will catch and built up on. If fasteners are needed, consider a flat rivet.

Andy Fulenchek
3. ensure an even temperature throughout the house

The final way I’d recommend you avoid condensation buildup within your dryer vent is to avoid your vent going through areas that are very cold. This might mean, for example, not running your air conditioning within the basement or leaving the door open to allow for heat distribution whilst the dryer is running. 

In extreme cases, contrasting temperatures might also cause condensation within the dryer!

4. use an electric dryer rather than a gas dryer

Gas dryers emit combustion byproducts, including carbon dioxide (CO2) and water vapor, as a result of burning fuel. The water vapor released during combustion can add to the overall moisture content in the dryer’s exhaust.

Rather than venting your gas dryer, an electric dryer will condense less water in your ductwork. 

4. Long Dryer Vent Ducts

A long and curvy dryer duct will cause a problem when moisture and water try to escape. Consult your dryer manual to verify your dryer’s rated vent length, but in my experience, dryer ducts should be no longer than 25 feet. The airflow will not be as efficient and smooth, resulting in water being left behind in the drying process. 

As well as a buildup of water, a long dryer duct is prone to a buildup of lint, which can be hazardous. Whenever installing a dryer duct, always try to limit the length of the run and the number of elbows. 

5 solutions to too-long dryer ducts 

Aside from the obvious which is redesigning your dryer duct to be shorter, there are a few other tactics you can try to omit the problems long dryer vents cause. 

Firstly, ensure your duct installation is correct. 4-inch ductwork is needed for longer runs, whereas using 3-inch ducts, as well as using lots of bends, creates backpressure and reduced airflow. This gives water more time to condense, and therefore water. Also, ensure your ductwork slopes to the exit to avoid pooling and leakage. 

The second option is to install a booster fan like this one (on Amazon). A booster fan is great for ducts that are longer than 10 feet and it’ll move air out faster and will remove lint easily. It can also improve the efficiency and drying time. 

The third option is to drill a small hole (⅜ of an inch) into the base of the pipe before it enters the laundry room’s wall cavity. Then install a pan or drain system to catch the water. 

Fourth, consider a ventless dryer. Most have what is essentially a heat pump (i.e. an air conditioner system running backward). They are ideal for homes that do not have interior-located laundry rooms on the first floor for instance, or basements where venting is difficult/impossible.

Finally, consider using a dryer vent filter bucket (on Amazon). It’s not my favorite option as it requires periodic maintenance and also increases the humidity inside the home!

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Hi, I'm Ed, and I run BuildFanatic! I enjoy providing the best possible information on a range of home improvement topics.

Andy Fulenchek
Owner at Grace Appliance | Website | + posts

Andy is a professional appliance repairman and business owner with years of hands-on experience. He co-authors and reviews appliance articles, ensuring accuracy and top-notch information for readers.

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