Bathroom Vent Leaks When It Rains

Many people complain that water is dripping from their bathroom vents because of leaky vents during the rainy season.

The bathroom vent leaks when it rains because of their vertical installation, hoses on the home’s roof, broken or defective covers, loose or missing dampers, condensation, damaged vent pipes, and broken flashings.

It is necessary to fix the problem because moisture can seep into the attic area and damage the wood studs. In addition, it can also cause bacterial and mold growth in the attic area because of the water presence.

Causes Solutions
Vertical installation of the vent hose Prefer horizontal installation
Vent pipes on the home roof Add hoods in the attic area
Broken or defective cover Install new vent hood covers
Loose or missing dampers Lubricate dampers
Condensation Install vents slightly away from bathtubs
Damaged vent hoods Seal the cracked area with epoxy
Broken flashings Add a flashing patch in the affected area

Vertical installation of the vent hose

These are the long pipes in the attic area for removing moist air and steam from the bathrooms and running with exhaust fans.

These pipes’ ending point or main hood is on the roof area to remove moist air and get fresh air. The fresh and dry air from the surrounding environment of your roof provides better ventilation and removes moisture from the bathrooms.

Many people install these bathroom vents in the vertical direction to redirect the airflow. The vertical installation increases the flow but allows the direct seeping of rain droplets into the pipes.

The rainwater from these pipes enters the exhaust fans, and you can see leakage there. The issue becomes severe when these are present without caps of louvers.

It is better to install them horizontally so rainwater cannot directly enter the pipes, move back to the bathroom, and come on their floors.

Use the flaps and covers to cover the opening point so water and contaminants cannot reach these areas.

Vent pipes on the home roof

Many people add the vent pipe on the roofs for better air circulation rather than on the attic area. They think the installation in the attic area damages studs and building constructions because of moisture.

In addition, it can also cause molds and bacterial growth in the attic area and decrease the strength of construction material.

The vent pipes on the roof are more vulnerable to damage because of direct UV exposure, heat, and other environmental factors.

Moreover, these are in exposure to rainwater which can cause leakage in the bathroom area and make the floor slippery and bad.

You can prevent them by installing the main pipes in the attic area. It is a safe place and also prevents them from environmental and weather changes.

The rainwater cannot enter the attic area and seeps through the pipework.

Broken or defective cover

Vent hood covers are made of two materials, including plastic and metal. These materials are susceptible to changes in the environment and allow water entry.

It leaks during rainy days because of water entry through these damaged or broken covers. In addition, many people do not know the correct size of covers for the hood on their roofs.

Using small covers leaves spaces on the sides and causes the problem. In addition, the covers are made of plastic material, which can get damaged by environmental factors.

The plasticizers lose their strength and flexibility when they come in exposure to heat and air for longer. In addition, the direct heat on them from sunlight exposure decreases their durability.

In addition, these can also break in the stormy season because of wind pressure. The plastic covers are not made of excessively durable materials that last longer.

Hail can also heavily impact them and lead to their breaking. It is better to replace the covers and flaps when you hear the noise from the exhaust vents.

The cold and hot air from these broken caps also inside the bathroom and cause fluctuations in interior temperature.

Loose or missing dampers

Most bathroom vents contain dampers at the pipes’ end to prevent air backflow. These are also known as backdraft dampers and prevent the entry of unwanted particles, pests, and bugs inside the interior.

Sometimes people forget to install them on the hood region while adjusting the ventilation system. Moreover, these also become non-functional when their flaps are stuck in one position.

The flaps of these dampers get stuck in one position and cause entry of water and air from the outside environment.

The dampers get stuck at the open position because of poor lubrication of the flaps. These are made of metal parts and corrode over time because of the moist air.

The moist air can corrode their bolts, which cannot close properly when air moves outside the connected pipes. In addition, the issue comes when screws are overtightened and not installed correctly.

It is better to add the dampers when these are broken, missing, or defective to stop rainwater entry and prevent leakages in bathroom areas.


Condensation is a common issue during the rainy season, which causes water leakage in the bathroom vents. In addition, the temperature drops during this season, and pipes become cold and trigger a condensation reaction.

The hot water from the interior side, when it comes in contact with cold pipes, produces steam and comes out in the form of droplets.

In addition, the issue also comes because of their installation at the wrong places. For example, the water vapor formation increases when installed directly over the bathtubs and showers.

The steam from the hot water of these vents comes in contact with the cold pipe and causes a problem.

Install them slightly away from the bathtubs and showers so warm air and steam cool down before reaching into the ducts to prevent condensation reaction.

Damaged vent hoods

The rainwater can travel through the ductwork and enter your bathroom when vent hoods are cracked or broken. These are present on your home’s roof for better airflow in humid interiors.

The heat and high temperature during summer seasons decrease the durability of plastic materials, and these can crack easily. In addition, these can also break from the sides when something heavy falls on them.

Heavy rain pressure, hailing, and storms can also develop cracks. In addition, the rainwater is slightly acidic and can erode the parts of metal vent hoods and eventually damage them.

It is better to add plastic hoods instead of metal because of corrosion. Seal the cracked area with epoxy to prevent further breaking.

Broken flashings

The flashings are the rubber or metal material installed near the hood of the vents to prevent water leakage from the roof area.

The roofs are drilled to make holes for pipe installation in these areas. The drilled roofs are sealed with flashings to prevent water leakage during rainy seasons.

Sometimes, the flashings get damaged because of their rubber material. In addition, the seasonal changes and temperature fluctuations cause the flashings to warp.

It leaves the spaces for water seeping when these shrinks because of seasonal changes. In addition, the issue also comes from their poor installation.

The flashings made of steel, cast iron, and metal material can rust easily. The rust can eat the metal and produce a hole, making space for water entry.

You can fix the leaking from the bathroom vent by plumbing cement and a flashing patch to seal the broken or cracked area.

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