Q. We just finished the installation of our walkway with bluestone 4 weeks ago. However, on almost every piece of the stone, there are different shapes and sizes of water stains like footprints or footballs on them and never go away even in the dry weather. Thanks.
A. What you’re seeing is likely not stains. It's not abnormal for the appearance of a brand new bluestone walkway installation to look less than perfect for a while. When irregular marks or shapes like those you describe show up a few weeks after installation, it usually means the stone is still going through its post-installation drying and curing process. Two common causes are efflorescence and trapped moisture.
Efflorescence happens when natural salts from the stone, mortar, or base materials move up to the surface as moisture evaporates. When the water dries, it can leave behind a hazy, cloudy, or even chalky-looking residue. This can form in random shapes that resemble stains. The good news is that efflorescence is harmless and temporary—it’s just a sign that moisture is still working its way out. As the walkway dries out and gets rinsed by rain or washed occasionally, those marks usually fade and disappear on their own within a few weeks to a few months.
Let's talk about uneven moisture retention. Bluestone is porous, so if the mortar or bedding layer underneath isn’t drying evenly, some parts of the stone stay darker than others. This often happens when the walkway is set on a damp base or when water can’t drain evenly underneath. The marks might follow patterns from the mortar bed, because those spots in the tile tend to hold moisture differently. As the weather warms and the base dries, this type of discoloration almost always evens out naturally.
Another possibility is that sealer was applied too early. If a sealer was applied right after installation, before the stone had fully dried, that can also cause an uneven or discolored appearance. In that case, the sealer can trap moisture underneath. Sometimes the only real fix is to remove the sealer, let the stone dry completely, and reapply sealer.
For now, the best thing to do is be patient and let nature work. Sun and airflow may help the stone and its base materials dry and stabilize. If the discolorations don’t start to fade after another month or two, or if a sealer issue seems likely, that might be the point where a professional stone and tile restoration contractor should have a look. An experienced PRO will be able to determine the right methods to safely restore the stone’s appearance. To find a vetted PRO in your area, visit www.surfacecarepros.com and click on Find a PRO.
ABOUT THE AUTHOR Fred Hueston is the Chief Technical Director at SurfaceCarePROS.com and Director at StoneForensics.com. He is also the author of Stone and Tile Restoration: The Manual, a comprehensive online manual for stone and tile restoration contractors. [Learn more about Fred.]
Article ID: 810
Created: November 12, 2025
Last Updated: December 4, 2025
Author: Fred Hueston
Online URL: https://surfacecarepros.com/kb/article/what-is-causing-water-stains-on-a-new-bluestone-walkway-810.html