Your gutter downspouts should not touch the ground. Otherwise, the rainwater might get backed up in the gutter until it starts overflowing.
But in other cases, like those with a particularly sandy or clay-rich soil composition, homeowners may choose to have their downspouts go directly into the ground. This helps to prevent pooling around a home's foundation, which can cause structural damage if left unchecked.
Instead, downpipes should outlet into surface water drains or soakaways, which allow rainwater to gradually soak into the ground safely. Directing downpipes straight into underground drains can overload them.
Installing a downpipe increases noise and exhaust emissions levels, which would make it non-compliant with local noise and air pollution regulations, even if it is "approved" (pretend then) with a 200 catalyst cells.
Gutters and gullies should only collect rainwater and connect to the rainwater drain. Wastewater pipes should not be connected to the rainwater system. If the rainwater gutters and gullies are connected to the wastewater drain, rainwater could overwhelm the drain and cause flooding.
Size of the Gutter Drainage Area: As a rule of thumb, one downspout should be placed every 25-35 linear feet of guttering. Depending on the local climate and rainfall intensity, some homeowners may need more downspouts. Many homeowners add extra downspouts to boost the drainage capacity of their gutters.
The Basics of Downspout Location
The cardinal rules for downspout placement suggest that they should be located at every corner of the house and approximately every 20 to 30 feet along the gutter line.
To ensure proper coverage and protection, bury your downspout extension at least 12 inches deep. This depth helps protect the pipe from surface activities and ensures efficient water drainage.
Underground downspouts are vertical pipes attached to the gutter of a house or building, which carry, lead, or redirect rainwater away from the building. Downspouts assits gutter drainage by carrying the water to the road, a nearby drainage system, or to the side of your home.
However, there are some common issues caused by buried downspouts that homeowners should be aware of. One of the most common problems with buried downspouts is clogging. Over time, debris such as leaves, dirt, and twigs can accumulate in the pipe, leading to blockages.
Many homeowners do not realize that their downspouts run into an underground downspout system, sometimes called a french drain. These underground downspout drains can get clogged as easily as your gutters can with leaves and debris.
Discharge/drain hole (vertical): 16-20 inches from floor. Fixture (side to side buffer): 15 inches minimum from centerline, 20 inches recommended.
Calculating Downspouts Based on Gutter Length
The general rule of thumb is one downspout for every 20-30 feet of gutter. This may vary depending on several factors such as the pitch of your roof, the volume of rainfall in your area, and the capacity of your gutters.
The right way to do it is to have the downspout end at least 12 inches from the ground level, leaving enough room to pitch the extension at the base without disrupting the flow of water. If the building is located at the top of a slope, you don't have much to worry about.
While homeowners may believe that gutters must abut the roofline, this assumption is incorrect. Ideally, gutters should be placed a few inches below the roofline. They need to extend beyond the roof shingles, not align with them.
To keep it easy, we recommend that you install one downspout every 20-40 feet of gutter. This will ensure that you are taking the proper precautions to defend against potential water damage to your house. The average home has 2-3 downspouts.
Typically, residential downspouts come in two sizes: 2x3 inches and 3x4 inches. The former is often used for smaller roofs, while the latter is preferred for larger homes. A 2x3 inch downspout can handle roughly 600 square feet of roof area for every inch of rainfall within an hour.
Install downspouts every 20 to 50 feet along the gutter. The more closely downspouts are spaced along the gutter, the more water can be conducted away during peak rainstorms.
Should Downpipes go into the Ground? No! The aim of a downpipe is to keep water away from the building, especially its foundations. As such a downpipe should direct water into a surface water drain or soakaway, which will allow the rainwater to gradually soak into the ground safely.
When a foul water drain has a problem, the property owner is responsible for repairs. If you're renting, check your lease agreement, as it may assign responsibility to someone else. Contact a drainage professional if you own your home and the issue is with a private drain.
Insufficient and poorly located downpipes are a frequent cause of poor roof drainage system performance. The installation of downpipes, especially near valley gutters, is designed to ensure rainwater from areas on the roof that have concentrated water flows is adequately removed.