Does Hard Water Cause Rust?

Does Hard Water Cause Rust

Have you ever come across rusty brown stains, perhaps in your bathroom, and wondered how they got there? Hard water is usually to blame and can cause much more damage than you think. Other than a green or white scale buildup, you may see nasty rust stains resulting from hard water.

Hard water can cause rust as it contains a high amount of iron, magnesium, and calcium. Calcium and magnesium in hard water cause scale buildup, but the large amounts of iron lead to rusting. When this iron is exposed to air, it becomes oxidized, leaving reddish-brown rust stains. The more exposure, the darker the color becomes.

If you have hard water in your area, you may have seen those brown stains on your bathroom sink or floor. Keep on reading to find out more about rust caused by hard water and its solutions!

Why Does Hard Water Cause Rust?

Hard water contains many minerals that can lead to rust and scale buildup in your bathroom sink, appliances, and pipes.

You may notice reddish or brownish rings in your bathroom or drain if your water is hard.

The high iron content in your water causes these stains. In deep water wells, the oxygen content is often low.

So iron, along with other minerals, remain dissolved in water. This makes these minerals invisible to the naked eye.

However, when this water reaches your taps and is used, it’s exposed to air.

As it’s exposed, the iron in water becomes oxidized, leaving behind reddish-brown stains.

Usually, hard water stains differ from the usual rust and iron stains and appear as chalky white residue, but sometimes, it can be iron and mineral-rich water causing the buildup of scale and brown stains.

Over time, these minerals can cause damage to toilet bowls, sinks, bathtubs, and even clothes as the buildup and stains worsen.

Signs Of High Iron Content In Water

If you think your hard water has a lot of iron content, you will be able to notice it in the following ways:

  • Rust-colored, reddish-brown stains on toilet bowls, sinks, and bathtubs.
  • Metallic odor or taste in water.
  • Reddish-brown stains on linen and laundry.
  • Tap water has a slightly yellow or red tint to it.
  • The water pressure is low. That can be a result of mineral buildup in your pipes.

3 Ways to Get Rid of Rust Stains

If you’ve experienced hard water rust stains around your home, there are several solutions to the problem.

Here are a few simple and easy ways to clean rust and hard water stains:

1. Use Elbow Grease and Vinegar

Many people have tried simple hacks like vinegar and elbow grease to remove rust and hard water stains. Use cleaning vinegar instead of regular one because it is more acidic and it helps clean the rust quicker.

Soak the stained area in vinegar for a few seconds and wipe it clean with a cloth. In most cases, this method works well, but you may need to repeat the process several times for stubborn stains.

2. Use Iron and Rust Cleaners and Removers

You can use rust and iron removal products available in homeware stores. They come in many different forms, from powders to liquids.

Liquid rust and iron cleaners dissolve stains but are more suitable for pipes and toilet bowls. It’s best to use powder versions to remove iron stains from household appliances’.

Iron cleaners usually contain metabisulfite or hydrosulfite that assists in removing these types of stains. Make sure to follow the directions given on the product you use.

3. Install A Water Softener

While vinegar and rust cleaners are short-term solutions to removing rust stains, you’d want a water softener for a long-term solution.

A water softener is a filter system that removes iron and other minerals from your water to soften it. They effectively absorb these minerals from your hard water like a sponge. Once the minerals have been removed, you will no longer get rust stains or scale build-up.

So, a water softener is the best option if you search for a long-term and permanent solution for these stains!

Water Iron Level Regulations

Under the National Primary Drinking Water Regulations, the Environmental Protection Agency has set standards for water contaminants, but the second regulation is flexible. Instead, these are just guidelines for the public and local water systems.

Around 15 contaminants are permitted to maintain the water’s odor, taste, and color. The maximum contaminant level for iron is 0.3 mg/L.

Public water systems only need to test voluntarily, as these are secondary standards. If your country doesn’t check for secondary measures regularly, it’s tough to see if your water’s iron levels are within limits.

If you don’t have a water filter at home, it can be challenging to note minor changes in your water.

However, when chlorine levels are high, you may feel a difference in the water’s odor and taste. Similarly, when the iron levels are high, the watercolor may change.


Can Hard Water Cause Rust On Stainless Steel?

Hard water can cause rust on stainless steel. It contains a high mineral content that can leave rust stains. Similarly, if heated, this water can leave deposits. Leaving these deposits breaks the passive layer and rusts stainless steel.

Does Tap Water Cause Rusting?

Tap cause may cause rusting over time. All types of water contain some level of oxygen dissolved in it. So, corrosion is a natural process that occurs in metal pipes. However, the rate of rusting for your pipes depends on your water quality.

Does Boiling Water Prevent Rusting?

Boiling water may prevent rusting, but it isn’t a well-used method. Under normal conditions, rust needs both oxygen and water. All gasses, including oxygen, are removed when you boil the water, so the risk of rusting is neutralized. That is how boiling water can help prevent rusting.

Final Thoughts

Hard water can be problematic. Scale build-up and rust stains, because of the iron in hard water, are significant areas of concern.

The good news is there are solutions available to you. You can choose to use a rust cleaner, remove the stains with vinegar or install a water softener for a more permanent solution.

The Filter Guy

Scott Birch is a water filtration installer and designer. He has worked in the industry for many years and is very familiar with and knowledgeable about residential water treatment equipment. Scott enjoys helping people get the most out of their water filtration systems and ensuring that their homes are getting the best possible quality of water.

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