Concrete splash blocks are an essential and often overlooked component of adequate landscape drainage. Properly installed around downspouts and other drainage outlets, splash blocks serve to divert water away from the foundation of a home or building, preventing erosion and water damage. This informative article will give homeowners and landscapers everything they need to know about selecting, positioning, and maintaining concrete splash blocks. 

With helpful tips from drainage experts, readers will learn the optimal techniques for integrating splash blocks into their landscapes. Whether seeking to upgrade old, damaged splash blocks or install new ones from scratch, this article will cover proper materials, sizing, placement, and ongoing care. With this valuable guidance, readers can feel confident installing durable and practical concrete splash blocks that will protect their properties from water issues for years to come.

What Are Concrete Splash Blocks?

Concrete splash blocks are protective barriers placed at the base of downspouts to redirect water away from foundations. They prevent soil erosion and water damage around homes by diverting water flow from downspouts away from buildings. Typically made of precast concrete, splash blocks come in a variety of shapes and sizes to suit different downspout types and water volume needs.

Purpose and Function

The main purpose of concrete splash blocks is to protect building foundations by preventing water from pooling around them. When rainwater exits downspouts at high volumes, it can erode soil and damage siding if not adequately diverted. Splash blocks redirect the water, dispersing it over a wider area so it can be absorbed into the ground at a slower rate. They also help prevent basement flooding by directing water away from building foundations.

Shapes and Sizes

Concrete splash blocks come in various shapes like rectangles, squares, and half-rounds. Sizes range from 6 to 24 inches long to suit small or large downspouts. For high-volume downspouts, larger splash blocks, at least 18 to 24 inches long, are recommended. The most common and versatile shape is the rectangle, which can be placed under any downspout type. Half-round shapes are ideal for round downspouts. Regardless of the shape or size, splash blocks should extend at least 6 to 8 inches from the downspout opening to properly divert water flow.

Placement and Installation

Proper placement and installation of concrete splash blocks is important for maximum effectiveness. They should be located directly under downspouts, spaced about 6 to 8 inches away from foundations. For the best results, splash blocks should slope away from buildings at a 30 to 45-degree angle. Burying a portion of the splash block in the ground, about one-third to halfway deep, helps stabilize them in place. Many splash blocks also have pre-drilled holes so they can be securely staked to the ground.

Benefits of Using Concrete Splash Blocks

Concrete splash blocks offer several advantages over other materials used for directing water runoff. 


Concrete is an extremely durable material that can withstand exposure to the elements without deteriorating. Concrete splash blocks will not rot, warp or break down over time like wood. They are also resistant to damage from insects and rodents. The durability of concrete splash blocks means they can last for many years without needing replacement.

Low Maintenance

Once concrete splash blocks have been properly installed, they require almost no maintenance. They do not need to be painted or stained and will not fade or scratch easily. Concrete splash blocks simply need to be cleared of any built-up debris to continue functioning properly. Their low-maintenance quality makes concrete splash blocks a very convenient choice.

Customizable and Decorative

While concrete splash blocks are very functional, they can also be customized and made decorative. Concrete can be stamped, stained, painted, or engraved to complement the style of a home. For a more decorative look, concrete splash blocks can be shaped into curves and angles instead of the standard square shape. Customized concrete splash blocks add visual interest to a yard while still serving an important purpose.


Concrete is an environmentally-friendly material composed primarily of water, aggregate rock, and cement. Concrete splash blocks do not contain harmful chemicals and will not leach any toxic substances into the surrounding soil. They can also be recycled into new concrete products at the end of their lifespan, reducing waste. The eco-friendly nature and recyclability of concrete make it an attractive choice for splash blocks and other landscaping elements.

In summary, concrete splash blocks offer durability, low-maintenance, customizability, and environmental friendliness. With so many benefits, it is easy to see why concrete splash blocks are a popular choice for managing and directing water runoff in many yards and gardens.

How to Install Concrete Splash Blocks

Proper installation of concrete splash blocks is important to effectively direct water flow away from foundations and prevent erosion. To install splash blocks, one must first select an appropriate location. The blocks should be placed at least 5 to 10 feet away from the building foundation, at the end of downspouts or where rainwater runoff flows. The ground should slope away from the building at a rate of at least 1 inch per 4 feet.

Preparing the Area

The area where the splash blocks will be installed must be level for maximum effectiveness. One may need to dig into uneven or sloped ground so the blocks can sit evenly. Any debris should be cleared from the installation area. It is also recommended to dig a shallow depression where the water will pool to give it a place to soak into the soil.

Installing the Blocks

Once the area is prepared, the concrete splash blocks can be put in place. For the most effective water diversion, multiple blocks should be arranged in a row with small gaps between each block. The blocks should sit level to one another to properly direct the water flow. They can be moved around as needed to create the optimal path for draining water away from the building foundation.

Securing and Finishing

There are a few options for securing splash blocks in place. They can be buried about one-third of their depth in soil, they can be staked into the ground using landscape stakes, or construction adhesive can be applied to the bottom of the blocks before placing them for a more permanent hold. For the best results, it is recommended to both bury the blocks partially in soil and stake them into place.

Finally, dirt, mulch, or gravel can be placed around the installed splash blocks to create an aesthetically-pleasing appearance and further help the water soak into the soil. With proper installation and maintenance, concrete splash blocks can provide effective and long-lasting water diversion and erosion control.

Concrete Splash Block Maintenance Tips

Proper maintenance of concrete splash blocks is essential to ensure their longevity and effectiveness. Concrete splash blocks should be inspected regularly for any signs of damage or deterioration and cleaned periodically.

It is recommended that concrete splash blocks be visually inspected at least twice a year, in the spring and fall. During inspections, check for any cracks, chips, or stains in the concrete. Small cracks can be sealed with concrete sealant to prevent water damage and further cracking. Large cracks or damage may require patching or replacing the concrete splash block.

Concrete splash blocks should be cleaned once a year or if they become excessively dirty or stained. First, remove any loose debris with a brush to clean concrete splash blocks. Mix a solution of water and concrete degreaser or detergent and scrub the splash blocks with a stiff brush to remove built-up dirt and grime. Rinse thoroughly with water to remove any remaining cleaning solution. For tough stains, scrub with an abrasive paste of baking soda and water.

Sealing concrete splash blocks with a concrete sealant, especially in areas with harsh weather conditions, can help protect them from water damage, staining, and cracking. Apply two coats of acrylic or epoxy concrete sealant, waiting 24 hours between coats. Re-seal concrete splash blocks every 2-3 years to maintain protection.

Proper installation and slope are also crucial for effectively functioning concrete splash blocks. Concrete splash blocks should slope away from the building at a rate of at least 1/4 inch per foot to allow for proper drainage. They should also extend at least 6 inches from the side of the building. Correct installation and slope prevent excess water from pooling around the building foundation, which can lead to water damage.

With regular maintenance and care, concrete splash blocks can provide many years of service diverting water from building foundations and preventing water damage. Following the recommended inspection, cleaning, and sealing procedures will keep concrete splash blocks in good working condition.


Concrete splash blocks are a practical and cost-effective solution for managing rainwater and runoff around your home. These sturdy, weather-resistant structures can help direct water away from your home’s foundation, preventing erosion and potential flooding. When shopping for concrete splash blocks, it’s important to look for high-quality, durable products that can withstand the elements. Rhino Concrete Danville, located in Danville, California, offers a wide selection of top-notch concrete splash blocks that are designed to last.

If you’re in the Danville, California area and are looking to install or replace your concrete splash blocks, Rhino Concrete Danville is here to help. Our team of experts can provide you with high-quality products, professional installation services, and guidance to ensure your project succeeds. Contact us today to learn how Rhino Concrete Danville can help protect your home’s foundation with durable and effective concrete splash blocks.

Frequently Asked Questions About Concrete Splash Blocks

Concrete splash blocks are rectangular concrete pads placed at the end of downspouts to divert rainwater from building foundations. They help prevent soil erosion and water damage to homes. There are a few common questions for those unfamiliar with concrete splash blocks.

Are concrete splash blocks necessary?

Concrete splash blocks are not always required, but they are highly recommended in many situations. They are handy for homes with basement foundations, crawl spaces, or homes built on a slope. Without splash blocks, rainwater can pool around the base of the home, seep into the soil, and possibly leak into the basement or crawl space. Splash blocks redirect the water to flow at least 5 to 10 feet away from the building.

What size splash block is needed?

The size of the splash block depends on the size of the downspout. As a general rule, the splash block should be at least as wide as the downspout opening and extend out 2 to 3 feet from the wall. A splash block at least 12 to 18 inches wide and 24 to 36 inches long for a typical residential downspout is usually adequate. It should have the sufficient surface area to diffuse the water flow.

How are concrete splash blocks installed?

Concrete splash blocks are installed at a slight angle, sloping away from the building. They are placed directly under the downspout, with the higher end against the wall. The ground under the splash block should be level and sloped away from the building for proper drainage. Some splash blocks have lips or ridges to help direct water flow. For the best results, install the splash blocks on top of gravel, crushed stone, or a concrete bed to provide stability and encourage drainage.

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