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What are Hard Water Stains?


*Reviewed by Ken Christopher, Senior Vice President at Rayne Dealership Corporation

No matter how many times you scrub your shower, you notice rings around the drain. Your faucets are caked in white splotches that come back again and again. What gives?

Stains don’t only come from dirt. They can come from water, too—specifically hard water. Hard water contains insoluble mineral deposits such as magnesium and calcium that can leave behind a stain on surfaces. The two main kinds of hard water stains are:

  • Soap scum 
  • Limescale 

Before you ask “is hard water bad for you,” let’s find out what hard water stains are and what they look like. This article will discuss both kinds of hard water stains as well as methods for eliminating and preventing them.

What Is Hard Water?

Generally, magnesium and calcium account for the minerals in hard water. These deposits are imparted from rocks and soils to rain and groundwater that eventually enter your municipal water supply.

Hard water is called “hard” because it’s difficult to form lather with.1 But not all hard water is the same; hardness varies by the grains per gallon (GPG) of minerals it contains:

Here is how hardness in water is typically measured:

  • Soft – Containing less than 1 GPG of dissolved minerals
  • Moderately hard – Containing 1 – 7 GPG of dissolved minerals
  • Hard – Containing 7 – 10 GPG of dissolved minerals
  • Very hard – Containing more than 10 GPG of dissolved minerals

What Do Hard Water Stains Look Like?

Unsightly chalky residue. Disgusting off-white solids. Film. Crust. 

These are some of the ways you’re likely to hear people describe hard water stains.

We’ve already noted there are two kinds of stains. These differ slightly in appearance.

  • Soap scum – Hard water doesn’t mix well with soap. That’s because of an interaction between the minerals of the water and fatty acids of the soap. It’s a common nuisance you’re likely to find in showers and sinks or on bathroom tiles. It’s typically a filmy, off-white substance, though it can also be grey. More than cosmetically undesirable, soap scum is also an invitation for mold and mildew, which appear in other unsightly colors2
  • Limescale – Also known as calcium carbonate, limescale comes from the heat-related breakdown of bicarbonate ions. That’s why you’re likely to find it wherever hard water and heat mix. If not addressed in time, limescale can build up, resulting in clogged and damaged pipes.3 Limescale appears as a white, powdery residue, especially on metal faucets.

It’s important to know what hard water stains look like. Once you know what you’re dealing with, it’s that much easier to take appropriate action.

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How to Get Rid of Hard Water Stains

When hard water evaporates, a mineral residue is left behind, causing a stain. While these stains can require a considerable amount of elbow grease, they’re not permanent. In fact, there are several methods for removing them. 

Next, we’ll look at a few homemade cleaning solutions that can remove these stains throughout the house.

Target Most Stains with White Vinegar and Water Spray

You don’t need a special cleaning product to start tackling your unwanted mineral deposits. White vinegar is easy to find and inexpensive—chances are you already have some on hand. Likewise, this spray is gentle on surfaces, so you don’t have to worry about making the problem worse. 

While you can use it straight from the bottle, a spray bottle will make the application easier. 

To assemble your cleaning spray:

  • Pour vinegar into a spray bottle.
  • Dilute the vinegar by half with distilled water.
  • Spray the hard water stain with the mixture.
  • Give the vinegar at least fifteen minutes to sit and break down the minerals.
  • Take a small brush or scrub pad and gently brush the stain. 

Not getting the results you want? Repeat the above process, slightly increasing the ratio of vinegar to water. 

You can use this spray on just about anything, from kitchen surfaces to your glass shower door. It’s a useful thing to have around the house for cleaning.

Tackle Hard-to-Reach places with White Vinegar and Paper Towels

What about those tricky, hard-to-reach surfaces, like the nooks and crannies of your bathroom, shower head, and sink knobs?

Once again, vinegar is your best friend, although you’ll need to use a slightly different application method.

  • Dilute vinegar with distilled water.
  • Soak paper towels in vinegar, allowing them to absorb fully. 
  • Ring out paper towels to keep them from dripping too much. 
  • Set, tie, or snake paper towels on or through the awkward area. 
  • Leave paper towels for at least fifteen minutes to saturate the stained area. 

Use Baking Soda to Tackle Tough Stains

While vinegar is ideal for visible, high-traffic surfaces, you don’t need to be as precious with your toilet bowl and sink. Baking soda paste can up the ante for hard water spot-cleaning bathtubs, tiling, and sinks. 

Assemble your paste as follows:

  • In a small container, add ⅓ cup of baking soda.
  • Sprinkle water slowly over the baking soda, stirring until a paste is formed.
  • Ensure the paste is sturdy enough to stick to vertical spaces without sliding.
  • Apply the paste and allow it to sit for at least fifteen minutes.
  • Thoroughly rinse.

With any luck, your surfaces will be restored to their original hue.

How to Prevent Hard Water Stains in the First Place

These methods are tried and true, but they’re not ideal—not everyone wants to spend their free time making sprays and pastes. And hard water stains are usually not one-time visitors. If yours persist, you may find you’re permanently adding extra vinegar and baking soda to your grocery list! 

So what’s the alternative?

Prevention is the best way to ensure you aren’t losing too much time to hard water stains. 

Water softeners and conditioners are ideal in that they prevent hard water stains at the source by removing hard water deposits. That way, calcium, magnesium, and other minerals never have a chance to wreak havoc on your sink and shower in the first place. 

Stop Scrubbing, Start Softening With Rayne Water

While it’s possible to remove the stains caused by hard water, the only long-term remedy is removing the mineral culprits from your water supply.

There are several ways to remove mineral and other hard water deposits from water. If water hardness is your only concern, a salt-free water conditioner can be ideal. Want to filter out viruses, bacteria, lead, and other particles, too? Reverse osmosis does it all.

Rayne Water offers a range of solutions to meet all of your home water needs. Call us today. We’re happy to answer any questions you have about hard water and the products we offer to treat it.


  1. Water Quality Association. Scale Deposits.,wasting%20properties%20of%20hard%20water/
  2. Florida State College at Jacksonville. Saponification: The Preparation of Soap
  3. Compound Interest. The Chemistry of Limescale

Expert Reviewer – Ken Christopher