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Blue-Green Water Stains in the Shower: Causes and Solutions

Often stains you see on plumbing fixtures are caused by chemicals and sediments in the water. Occasionally, rust will produce more dramatic and darker stains.

But have you ever noticed blue-green stains in your shower or on the bathtub?

These are not your typical water stains. They occur if your plumbing system uses copper pipes and fittings. This color buildup makes your white porcelain look dirty and ugly.

Check out what’s causing the ugly blue-green stains in your shower and on the bathtub, how to get rid of them, and how to prevent them from happening in the future.

blue stains on a sink
Source: Clean Water Systems and Stores

What Are Those Blue-Green Stains in Your Shower

Water often causes the ugly blue-green buildup on your bathroom fixtures. However, unlike other types of water stains, this buildup only occurs if you use copper pipes and fittings in your plumbing system.

If there’s too much copper in the water, it will leave bluish-green stains where water sits. That’s why you can usually find this colored buildup in the drains of your sink, shower, and bathtub.

Possible Causes of Blue-Green Water Stains In the Bathroom

Even though you can get rid of the blue-green stains in your shower and bathtub, if you don’t deal with the source, it will return. There are a couple of possible causes behind the blue-green water stains on your white porcelain.

Mold and Mildew

Mold and mildew come in different kinds. One of the common types you often deal with in the bathroom is Penicillium, which is mold fungi with green or blue hues. Besides causing an unsightly buildup on your porcelain or the shower drain, this mold is also harmful to the human body.

Mold and mildew are responsible for the blue-green buildup when:

  • The gunk has a velvety, fluffy, and hairy texture.

  • Mold groups and grow together, so you’ll find this colored water stain in darker and discolored patches.

  • Mold causes damage to the surface it grows on. So if there’s peeling or curling of paint, vinyl, and other materials around the blue green gunk, it’s most likely the mold causing it. 

How to Deal with Mold and Mildew

You can remove existing mold growth using a mold and mildew disinfectant. However, it’s important to remember what causes mold to grow in your bathroom in the first place. Bathrooms are often home to mold growth because of the excessive moisture, so the best way to get rid of mold and mildew, in the long run, is to control any leak or moisture.

A couple of things you can do to prevent further mold growth that causes blue-green stains in your shower and bathroom includes:

  • Wiping off the walls after showering
  • If you use tiles on your shower walls and floor, seal all grout lines to avoid moisture getting trapped in dark, tight spaces where blue mold can grow
  • Turn on the air conditioner or bathroom fan after bathing or showering to reduce any excess moisture

Limescale Deposits

Another possible cause of the blue-green gunk in your shower and bathtub is the limescale. Scale deposits can build up due to hard tap water, which contains dissolved minerals. Limescale is often white, but it can turn to a bluish-green hue when your plumbing system has copper pipes and fittings.

You’ll know if the blue-green stain is caused by limescale if it has a chalk-like, crusty appearance. You can often spot these around your bathroom tap, bathroom sink drain, and on the tiles in your shower.

How to Deal with Limescale Deposits in the Bathroom

Hard water is the main culprit of limescale. To keep it at bay and prevent further buildup of blue-green chalky stains in your shower and on the bathtub, you can add a water softener to your tank or water supply. You can also install an ion-treated water softener unit to remove any stain-causing mineral deposits from your water.

Corroded Piping

When piping materials break down, some of their components mix with water. If you’re using copper pipes and fittings, the copper component can easily combine with water. The excess copper in water causes copper staining, which you see as the blue-green buildup in your shower and on the bathtub.

Pipe corrosion happens when pipes are exposed to corrosive elements. Using two different kinds of metals in your plumbing can cause electrolysis, a process that speeds up metal corrosion. An example is a copper pipe attached to a galvanized steel pipe. The more reactive metal, which is copper in this case, will start corroding, leading to the blue-green stains on your plumbing fixtures.

Check out your piping system and if you find two different piping materials connected, one might be corroding and causing the blue-green tarnish.

How to Deal with Pipe Corrosion

There’s only one way to deal with corroded piping and that is to replace it. You can either use a similar metal pipe throughout the plumbing system or change it to a nonmetal piping to eliminate further corrosion issues.

Corrosive Water

Water can be corrosive, which can become a problematic condition for homeowners. This aggressive water can dissolve and damage materials that it comes in contact with, including metals in your plumbing system. For instance, corrosive water can damage your copper pipe, which may cause bluish-green stains in your shower and on the bathtub.

Symptoms of corrosive water include:

  • Metallic tastes in the water, especially first thing in the morning
  • Small leaks in your plumbing system

How to Deal with Corrosive Water

There are several ways to solve blue-green stains in your shower caused by corrosive water, but it might require more plumbing work.

  • Treat your water supply to make it less corrosive. Chemical feed systems and neutralizing filters can help reduce water corrosivity
  • Replace the plumbing system components with corrosion-resistant pipes
  • Reduce metal concentrations in your water by replacing copper pipes and fittings

How to Get Rid of Blue-Green Water Stains in Your Bathroom

Preventing the problem is one thing, but what about the blue-green water stains that are already on your plumbing fixtures? Can you get rid of them? How?

There are many ways to get rid of the water stains in your bathroom that will also work in taking out the blue-green buildup. You can use homemade cleaners or use the commercial cleaner that you already have at home.

  • White Vinegar and Water Solution

Vinegar combined with water is a common homemade cleaning solution that works well on a lot of stains. Let the solution sit on the affected surface in your shower or bathtub and the stain should start to lift after a while. If not, try gentle scrubbing on the area with a non-abrasive sponge.

Vinegar is a weak acid, so it should be safe to use on any fixture material.

  • Lemon Juice and Cream of Tartar Cleaner

Lemon juice, like vinegar, is an excellent cleaning tool safe to use on most bathroom fixtures. You can create a slightly acidic sticky paste out of lemon juice and cream of tartar that can get rid of copper stains.

  • Ammonia and Water Solution

If milder acid solutions can’t get rid of stubborn blue-green water stains, you can go up a level by using a cleaning solution made from mixing ammonia and water. Let the stain soak in the solution then follow up with gentle scrubbing using a non-abrasive sponge.

  • Commercial Cleaning Products

Many commercial cleaning products can also do the trick of getting rid of stubborn copper stains. For instance, cleaners with sodium bisulfate or any other harsh chemical cleaners work well. However, don’t forget to do a spot-check using the solution in an unobtrusive area of your fixture to check if you’re not trading one problem for another.

To remove blue-green stains, start with the gentlest cleaning solution, then work your way up to more powerful abrasives and stain cleaners as you need them. Thus, you won’t end up causing unnecessary damage to your fixture’s surface.

Mandy Phillips

As a frequent contributor to top US magazines and publications in the home improvement niche, Mandy has been known for sharing her expertise on how to clean, organize, and decorate bathrooms.

Additionally, Mandy has immense experience offering lifestyle tips and tricks to her readers.

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At Loo Academy, our mission is to offer trusted advice for everything related to bathrooms (design ideas, plumbing advice, showering & bathing tips, remodeling guides, and more) — a place where we all spend a great deal of time.

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