The Cleaning Staple That'll Eliminate Water Marks On Granite Countertops
If your granite countertops aren't properly sealed, you might have encountered the most frustrating of all stains: the water mark. Water stains drive us crazy not because they're particularly unmanageable but because any reasonable person expects to be able to get water on a countertop without staining the stone. It's tantamount to walking outside one day and noticing that you've gotten air stains on the side of your house. Fortunately, these stains are usually easy enough to fix with a mixture you should already be using around your home to clean: hydrogen peroxide and baking soda.
Water stains happen at the intersection of a couple of issues. One problem is that granite, being a natural stone, is porous to some extent. Another is that our water often contains minerals, especially if we have "hard water," and those minerals like to collect and create stains. (It could be worse — some drinking water purified from wastewater is so pure that it can cause health issues, including arsenic poisoning. We'll take the hard water, please.) These stains aren't normally that difficult to manage, especially when you're scrubbing them from smooth plastic, stainless steel, or enameled surfaces in your bathroom or kitchen. But, being porous and often not well-sealed, granite is not as smooth as it might seem.
Banish water marks with hydrogen peroxide and baking soda
The best method for getting rid of hard water stains on granite is with a paste of 3% hydrogen peroxide and baking soda. The exact proportions aren't as important as the consistency, which should be similar to peanut butter. This baking soda/hydrogen peroxide paste will usually clean as well as any safe, commercially available solution and is often a better choice for surfaces like granite that don't take kindly to abrasive cleaners.
Spread the paste directly on the stained area and let it stand for around 10 minutes. Use a soft cloth, slightly damp, to wipe away the paste and the stain. If the stain persists, repeat all this, but after applying your paste, cover it with plastic wrap, tape at the edges, and let it sit for 24 hours. The soft-cloth cleanup will almost certainly get rid of the remainder of the water stain.
After a thorough cleaning, it's time to consider sealing your granite countertops. Not all granite requires sealing. If you have darker granite and water tends to stand on it longer than a half-hour or so, sealing it might not accomplish much. You can test your countertop's porosity with a simple test using nothing but water. After sealing, take care not to use harsh cleaners that might damage or remove the sealant.