Where Does Water Go on a Flat Roof?

aerial view of neighborhood with flat roofs
As a homeowner or business owner with flat roofing, you may be wondering what happens to the water on your roof when it rains or snows. After all, flat roofs don't have the benefit of natural slopes to guide water towards a specific location. The answer depends on whether or not you have a roof drain system in place, and what system you have.
In this blog, we'll discuss the importance of a proper drainage system for flat roofs and explore some of the most common flat roof drainage solutions.

The Importance of a Proper Drainage System

rainwater leaking over the side of a roof
A proper drainage system is crucial for maintaining the integrity of your flat roof. Despite most roof membranes being water resistant, the accumulation of water on the roof surface can cause roof damage in the form of leaks and the premature deterioration of roof materials.
Both of which involve expensive repairs. Standing water can also attract pests and mold growth, which can pose health hazards to occupants. Because of these costly risks, ensuring proper drainage is something you cannot overlook if you have a flat roof.

Drainage Systems for Flat Roofs

gutter snaking down the side of a home
There are several types of flat roof drainage systems available for flat roofs, including interior drains, gutters, and scuppers. Each of these options has its advantages and disadvantages, and therefore the best drainage system will depend on various factors, such as the size and shape of the roof and local climate conditions.


Interior roof drains, also known as internal drains, are a popular choice for flat roofs, especially in areas with heavy rainfall. These drains are typically installed in the center of the roof and use a series of pipes to channel water away from the roof and into a designated drainage area. Interior drains are a discreet and efficient solution for flat roofs, but they do require regular maintenance to ensure that they remain clog-free and in good working condition.


Gutters are another common option for flat roofs, and they are a great way to direct water away from the roof's edges. They work by collecting water as it runs off the roof and channeling it towards downspouts that deposit the water away from the building foundation. Gutters come in various materials, such as aluminum, steel, and copper, and can be customized to match the building's aesthetic.


Scuppers are openings in the walls or parapets of the roof that allow water to drain off the roof and onto the ground. They are a cost-effective drainage solution that can be easily installed during flat roof repair. Scuppers are typically used in combination with tapered insulation, which is designed to create a slope on the roof surface that guides water towards the scuppers.

The Roofers are Your Source for All Your Roofing Needs

At The Roofers, we understand flat roofing and account for the risks standing water poses with proper drainage. We also are committed to providing every one of our customers with cost-effective solutions that meet their unique needs. Whether you need modified bitumen roofing, 4-ply flat roofing, or single-ply flat roofing, we have the expertise, experience and the roofing systems to get the job done right.

Contact us today to learn more about our roofing services and get a free roof estimate from one of our roofing experts.