Turns out, a $10 piece of molded plastic, or concrete if you’re fancy, can cost you thousands if it’s installed wrong.
Yep, I’ve seen it more times than I can count. Water running the wrong way, splash blocks pointing toward the house (I wish I were joking), and folks wondering why their basement smells like a swamp.
A splash block might seem like a no-brainer. You plop it under the downspout and forget about it, right?
Wrong.
Done incorrectly, it can quietly wreak havoc on your home’s foundation, lawn, and even your indoor air quality.
So, let’s get this straight: this isn’t about impressing the neighbors or slapping a decorative stone under your gutters to “check the box.”
This guide is about doing it right the first time—because correcting poor drainage after the fact? That’s a wallet-buster.
You might be asking:
“Do I even need a splash block if my gutters drain onto gravel?”
“Why do all my neighbor’s blocks face the wrong way—am I missing something?”
“Can I just flip it around so it doesn’t mess up my mulch bed?”
Those are great questions. And if you’ve ever looked at your splash block after a storm and thought, “Is it... doing anything?”—you’re in the right place.
What Is a Splash Block and What Does It Actually Do?
Photo Source -> Nebraska Extension Publications - University of Nebraska–Lincoln
A splash block might look like the least exciting part of your drainage setup, but it’s the unsung hero when it’s installed properly—and a silent villain when it’s not.
At its core, a splash block is a ramp. A ramp that takes high-speed water pouring out of your downspout and redirects it away from your foundation. That’s it. No moving parts, no electronics, just simple physics.
But here’s the kicker: the direction and slope of that ramp matter a whole lot more than people think. If it’s angled the wrong way—even by a couple of degrees—you’re not “channeling” water, you’re inviting it to party in your basement.
Let’s talk specifics:
Redirects water away from your home’s foundation. This is the big one. Without that redirection, water can pool and seep into your footings. That’s how cracks, leaks, and mold problems begin.
Prevents soil erosion and trenching. Ever notice those deep gouges in flower beds beneath a downspout? That’s what happens when you skip a splash block—or use one wrong.
Protects against structural damage. Over time, even a slow trickle of water can degrade masonry, rot siding, or shift foundations. It doesn’t take a flood—just consistent, unmanaged runoff.
Choosing the Right Type of Splash Block
Size and Shape Matter
A dainty little 8" splash block under a 3x4 commercial downspout in a rain-heavy region? That’s like catching Niagara Falls with a salad bowl.
Here’s how to size it right:
Match your block to your downspout size. The wider the downspout, the more water it’s handling. You don’t want that volume flying off the edge of a narrow splash block and digging trenches in your mulch.
Match your block to your region’s rainfall. If you live in a place that gets hammered during storm season (looking at you, Florida), go big. The more surface area the block has, the better it can slow and direct the flow.
Wide vs. narrow designs. Wide blocks are great for diffusing flow gently across gardens, gravel, or sod. Narrow blocks are better when you want to channel water in a straight, focused stream—like toward a drain or away from a tight corner.
Materials: Concrete vs Plastic vs Decorative
Concrete Splash Blocks
Photo Source -> Entomology - University of Kentucky
The tank of the bunch.
Ideal for high-volume water or areas where you don’t want movement.
Won’t blow away or shift—but you’ll need a strong back or a helper to install them.
Perfect for commercial properties or steep slopes where erosion is a concern.
Plastic Splash Blocks
Lightweight and easy to move around (especially for DIYers).
Great for average rainfall zones or temporary setups.
Just know they can shift after storms if not anchored well, and they don’t hold up to landscaping tools the way concrete does.
Decorative Splash Blocks
Some are functional. Some are just for show. Know the difference.
A frog-shaped splash block is cute until water pours out the side and kills your begonias.
We’re all for form and function—but function comes first. Pick decorative blocks that still slope properly and channel water where it needs to go.
Step-by-Step – How to Install a Splash Block Correctly
This is where the rubber meets the road—or rather, where the rain meets the dirt. You’d be shocked how many folks install splash blocks like they’re garden gnomes: just toss 'em under the downspout and hope for the best. But proper installation takes maybe 15 minutes, and it’s well worth it to avoid the cost of repairs later.
Let’s walk through it the AquaBarrel way—quick, correct, and built to last.
Tools & Prep Checklist
You don’t need a full toolbox to install a splash block, but having a few basics will make your life easier:
Shovel or trowel – to dig and level the area.
Measuring tape – to ensure proper spacing from the house.
Level – even a cheap bubble level works, just to verify that water is flowing the right way.
Optional: hose – for testing your work (we recommend this).
Before you start digging, take 30 seconds to look at the slope of your yard. Does it naturally tilt away from your home? If not, you’ll need to create that slope yourself—or the splash block could backfire and send water toward your foundation.
Installation Instructions
Step 1: Locate Your Downspout and Clear the Area
Brush away mulch, gravel, or grass. You want a stable, solid spot to work with. Don’t install on top of soft material—it’s going to shift the second it rains.
Step 2: Dig a Shallow Trench (If Needed)
You’re not building a moat—just enough of a dip so the splash block can sit at a slight angle away from the home. Even a 1–2 inch difference from back to front can do the trick.
Step 3: Place the Splash Block with the Closed End Against the House
This is where a lot of people get it wrong. The closed end goes flush to the house, right under the downspout. That’s the part that catches the water.
?? “But Barry, all my neighbors have them the other way around!”
Yeah, and I bet some of them leave their Christmas lights up year-round too. Don’t follow bad habits—do it right.
Step 4: Ensure It Slopes Away
Use your level to check. If the front (open end) is higher than the back, water will pool or run back toward your foundation. Not good. Re-dig if needed.
Step 5: Test with Water
Run a hose through your downspout or wait for a solid rain. Watch where the water flows. If it pours off the end and away from the home, congrats—you nailed it.
?? Pro Tip: Don’t just drop it on top of mulch or grass. Bury the splash block slightly into the soil so it doesn’t shift after every rainstorm. Even plastic ones need that stability. If you're worried about movement, place a flat stone or brick underneath as a base—it works wonders.
Common Mistakes (That Could Cost You Big)
You’d think splash blocks would be hard to mess up—after all, they’re literally just blocks. But oh boy, you’d be surprised how many homes I’ve seen with water pouring back toward the foundation because someone skipped the basics. Whether it was a rushed builder, a well-meaning DIYer, or a landscaper who just eyeballed it—these little mistakes add up fast.
Let’s cover the most common (and most costly) flubs I see in the wild.
Facing the Wrong Direction
This one is the big kahuna. If you only remember one thing from this guide, make it this:
?? The open end of the splash block goes away from the house. Always.
Sounds obvious, right? You’d think so. But I can’t count how many new developments I’ve driven through where every splash block is installed backwards. It’s almost like the builders handed out a memo: “Install these facing the foundation and call it a day.”
If your splash block looks like it’s “catching” water rather than channeling it away? Flip it. Immediately.
Letting Them Sit Uneven or Misaligned
Even if you’ve got the splash block facing the right way, your job isn’t done yet.
If the back end is higher than the front? Gravity’s going to do what it does best—and that water will head straight back toward your home.
You’d be amazed how often I’ve seen a block that looks fine at first glance—but is off by just a few degrees. Water doesn’t need much encouragement to go the wrong way.
Here’s what to do:
Use a level during installation.
Re-check after heavy rains or freeze-thaw cycles. Soil shifts. Blocks settle.
If needed, dig out under the front or build up under the back to maintain the correct slope.
Bonus tip: Don’t trust your eyes. What looks “sloped” might not be. Trust the level—or better yet, run some water through and watch what happens.
Ignoring Soil Erosion After the Block
Sometimes the splash block is working... a little too well.
You’ve got all that water shooting off the end of the block, and now your mulch is washing away, or there’s a muddy trench carving through your flower bed. That’s not a splash block failure—it’s a follow-through failure.
Here’s how to fix it:
Add a bed of gravel or river rock where the water exits.
Place a stepping stone or flat paver to help diffuse the flow.
Consider a downspout extension if the splash block alone isn’t cutting it.
Remember: A splash block gets water away from your foundation—but where it lands after that still matters. Don’t trade one drainage issue for another.
What If the Yard Slope Works Against You?
Now let’s talk about the stuff splash blocks can’t fix on their own. Because sometimes, the problem isn’t the block—it’s the land it’s sitting on.
You’ve got a beautiful new splash block installed. It’s facing the right way. The slope looks decent. And yet… after every rain, water is still hugging your foundation like it’s trying to move in rent-free.
Sound familiar? Welcome to the joys of bad grading.
When Grading is Flat or Sloped Toward the Home
This is one of the most frustrating scenarios we see. The yard doesn’t naturally drain away from the house, or worse—it slopes back toward it.
If your splash block is sitting on level ground (or slightly uphill), all it’s doing is giving water a comfy runway back to your basement. Here's how to fight back:
Dig a deeper trench where the splash block sits. Even creating a slight angle—an inch or two over a couple feet—can make a huge difference. You’re basically re-engineering gravity on a small scale.
Use downspout extenders. Splash blocks are a great start, but if your grading is working against you, you’ll need to move that water farther away. Extensions help carry runoff several feet out—beyond the problem zone.
Underground drains are your long-term MVP. If you’re in a tough spot with no slope, tie your downspouts into underground PVC or corrugated piping. Done right, these systems disappear into the yard and send water safely into daylight drains, swales, or even a dry well.
It’s not cheating—it’s just smart.
Smart Alternatives or Add-Ons
At AquaBarrel, we’re big believers in giving water a place to go. Splash blocks are part of the solution, but when you need more than a passive slope, these upgrades will do the heavy lifting:
Aluminum Downspout Extensions (Kick-Outs)
Durable and rigid.
Best for straight runs where you need water to travel an extra 2–4 feet from the house.
They blend in nicely with your existing downspout.
Corrugated Drain Tubes
Flexible black tubing that snakes through your landscape.
Ideal when you need to weave around gardens, walkways, or tight corners.
Great for longer distances or trickier layouts.
Flip-Up or Roll-Out Extensions
Flip-up models hinge out of the way for mowing and yard work.
Roll-outs extend automatically when it rains, then retract when dry.
Not as durable long-term, but perfect for folks who want convenience without a permanent install.
Rain Barrels with Overflow Diverters
Now you’re speaking our language. Rain barrels don’t just solve the slope issue—they capture the water for reuse. Combine them with a diverter and overflow setup to control runoff even during storms.
Pro tip: If you install a rain barrel on a flat yard, elevate it slightly and use the overflow port to guide excess water safely away. That way, you're not just avoiding water damage—you’re turning it into a resource.
Do the Ridges Help Diffuse Water?
This one makes me sigh.
Some people (including a few home inspectors, unfortunately) will tell you the ridges in a splash block are designed to “diffuse” or “spread out” water.
Wrong.
Those ridges are there to guide the water in a specific direction—not to mist it across your lawn like a sprinkler. Water needs to be directed, not diffused. You want it flowing in a clear, controlled path that leads away from your home.
So, no—the ridges are not the reason you face the block one way or another. The slope and orientation are what matter.
Bonus Tips for Long-Term Success
Alright, you’ve installed your splash block the right way, pointed it in the right direction, and maybe even upgraded it with an extension or rain barrel. Now what?
Well, like most things around the house, it’s not “set it and forget it.”
With a little attention—and a few smart landscaping tricks—you can keep your splash block working for years and make it blend right into your yard like it was always meant to be there.
Maintenance Checklist
A splash block doesn’t need a ton of babysitting, but it’s not fire-and-forget either. Especially right after a new install, keep an eye on it for the first few storms. Here’s what to watch:
Inspect after every few rains. Check for shifting, tilting, or signs it’s not draining properly.
Look for standing water—either in the block or around it. That’s a red flag.
Watch out for mosquito breeding. If water pools in or around a backwards-facing or sunken splash block, you might be accidentally creating a bug spa.
Clear debris. Leaves, mulch, and even grass clippings can build up in front of the block and disrupt flow.
If something seems off—adjust it. Trust your gut and the direction of the water.
Small Fix. Big Impact.
Here’s the bottom line: A splash block is about as simple as it gets, but when it’s installed wrong, it can cause serious damage. And I’m not talking about a little yard puddle. I’ve seen backwards splash blocks lead to basement mold, foundation cracks, and homeowners stuck with five-figure repair bills… all because water wasn’t redirected the right way.
The good news? This is one of the easiest problems to fix—and one of the smartest upgrades you can make for long-term protection.
Just remember:
Face the open end away from the house.
Check your slope.
Don’t assume the builder or your neighbor got it right—check for yourself.
Anchor it in place, inspect it after storms, and upgrade if your slope or soil needs more help.
At AquaBarrel, we’ve spent the last 20 years helping folks like you outsmart water, one downspout at a time. Whether you need a basic splash block, a commercial-sized extender, or a full rainwater harvesting system—we’ve got the parts, the knowledge, and the support to make it easy.
?? Ready to install the right way?
Explore AquaBarrel’s full line of downspout accessories—from adapters to diverters, extensions to rain barrels. We don’t just sell parts; we solve problems.
Because around here, it’s not just about drainage—it’s about protecting what matters most.