3 Telltale Signs Your Paver Application Isn’t Draining Properly

Proper drainage is one of the most critical elements of a successful hardscape installation. Without it, even the most beautiful patio or walkway can quickly become a problem area—leading to joint failure, surface staining, and even structural damage over time. Fortunately, a paver project will usually let you know when something’s wrong.

Here are three telltale signs your paver application isn’t draining properly:

1.) Moss, mold or mildew growth

Greenish patches of moss, dark mildew, or that telltale musty smell, are signs that a hardscape surface may be retaining too much moisture. These organic growths thrive in damp, shaded environments—usually indicating that water is lingering on or just beneath the surface. While occasional growth is normal in certain climates, consistent buildup is a strong clue that the system isn’t draining as it should.

Tip: Check if the affected area is low-lying or heavily shaded. Poor grading or clogged bedding layers may be to blame. Be sure any surface drains are not clogged either.

2.) Dark Paver Joints

Polymeric sand joints should return to a consistent, dry appearance after rainfall. If some of the joints remain dark long after the rest of the surface has dried, there’s a good chance water is sitting in those joints—or worse, below them. This trapped moisture can weaken the polymeric bond, shorten the lifespan of the sand, and lead to weed or moss intrusion. And trapped moisture in the bedding and base materials can lead to settling and unsightly or even structure issues with your project.

Tip: Try gently probing a joint with a flathead screwdriver. If it crumbles easily or feels soggy, this could mean the project is not draining properly.

3.) Standing water

Pooled water on the paver surface or between joints means the area is either not pitched correctly, or water is unable to escape through the base layers. Over time, sitting water can compromise the integrity of the base, stain the pavers, and encourage erosion in nearby joints.

Tip: Use a level or string line to check for proper pitch (minimum 1/8" per foot away from structures). Make sure your base and bedding layers are properly compacted and well-draining. You might also consider performing a drainage test. You can do this by filling questionable joints up with water and seeing how long it takes to move off the surface. A minute or two would indicate decent drainage while 5-10 minutes would indicate poor drainage.

Final Thoughts

Drainage issues can quickly deteriorate a hardscape installation, especially in climates with heavy rainfall or freeze/thaw cycles. Accounting for proper drainage at the onset of the project will prevent big headaches down the road. A well-draining paver system isn’t just good practice—it’s essential for long-term performance.