Why Do I Have Red Residue from Water?

Water leaves a red residue when it contains iron or bacteria.

Fortunately, solutions exist to clean red water stains and remove them for good!

Do you keep noticing red stains in the shower from your water? If so, then you’ve probably also encountered red residue in your bathtub, sink, toilet and other water-using appliances.

Where are these unsightly red blemishes coming from? In this post, we’ll tell you everything you need to know about this problem and how to solve it.

Keep reading to learn:

  • The potential causes of red residue from water
  • The health risks associated with these causes
  • How to get rid of red stains from water
  • How Angel Water can help you keep these stains gone

Why Does My Water Leave a Red Residue?

The two most common causes of red residue from water are iron and Serratia marcescens bacteria. Iron contamination occurs when high concentrations of iron get into a home’s plumbing system. Conversely, Serratia marcescens bacteria do not usually grow within plumbing pipes. Instead, they congregate in moist, oxygen-rich environments, such as toilet bowls or tubs.

Iron is the fourth most abundant element in the earth’s crust. It frequently infiltrates underground private wells, and since those wells receive no municipal treatment, it finds its way into the home. City water can also have iron contamination from old iron pipes.

Serratia marcescens is a type of naturally occurring bacteria typically found in soil, food and animals. These airborne bacteria seek moisture-rich areas to congregate, and they thrive and grow by consuming phosphorous or fatty substances, such as poop residue in a toilet or soap scum in a sink.

Let’s take a closer look at how each of these impurities causes red water stains in showers and bathtubs.

How Iron Causes Red Residue from Water

Iron takes two different forms in water: soluble ferrous iron and insoluble ferric iron. Both types cause red water stains, but it’s important to identify which type you have because each requires a different solution.

Soluble ferrous iron in water is invisible to the naked eye when fresh out of the tap. However, when the ferrous iron is exposed to the oxygen in the air for a long time, a chemical reaction occurs that turns the iron a rusty red color. This reaction also causes iron bacteria to grow, which have a red, slimy appearance. The surrounding surfaces are stained red as a result.

Unlike soluble ferrous iron, you can see insoluble ferric iron floating in your glass of water. This type of iron has already been exposed to oxygen, which turns it red. As a result, your water will have a rusty red appearance when you pour it from your tap.

How Serratia Marcescens Causes Red Stains

As we mentioned above, Serratia marcescens bacteria occur naturally and travel through the air to high-moisture environments. The standing water in a toilet bowl or leftover puddles in a tub after bathing are particularly vulnerable to Serratia marcescens infiltration.

Serratia marcescens growth is especially likely in water that does not have chlorine in it. Filtering chlorine out of the water in your home is essential to protect your health. However, chlorine also helps protect standing water from bacteria like Serratia marcescens. So, the stains caused by these bacteria are an unfortunate side effect of dechlorinating your water. But we think having to clean these stains is better than dealing with the harsh health effects that drinking or bathing in chlorinated water can cause.

How to Distinguish Iron Stains from Serratia Marcescens Stains

So, are those red stains in your shower stall caused by iron or Serratia marcescens? There are a few ways to distinguish between the two. One is the color of the stains. Iron stains tend to be on the darker red or orangish side, while Serratia marcescens stains are usually pinker.

Another factor to pay attention to is if the stains are more constant or tend to come and go. Serratia marcescens stains tend to come and go because the bacteria often infiltrate the home after certain events. For example, they can get in during the summer months when the windows are open or after construction or home renovation projects that stir up dirt and dust. Iron stains, in contrast, tend to be more constant because of steady iron contamination year-round.

Paying attention to the above factors will give you a hint at what you’re dealing with. The only way to know for sure is to get your water tested. We’ll discuss water testing in more detail below.

Other Problems Associated with Red Residue from Tap Water

These red stains are certainly embarrassing and annoying, but can they also threaten your health or cause problems in your home? The good news is that neither iron nor Serratia marcescens are likely to cause any health problems.

Drinking water with iron in it is good for the body because it needs iron to transport oxygen in the blood. It only becomes a threat to human health if iron concentrations become dangerously high, but this is extremely rare.

Serratia marcescens has been known to cause infectious diseases, such as urinary or respiratory tract infections. But this typically only occurs in medical environments and in people with compromised immune systems or underlying health issues. Serratia marcescens bacteria in tubs, showers or toilets are not as likely to cause these problems in healthy households.

Iron and iron-reducing bacteria in water can also create problems within the home, including:

If you’re sick of these stains and the problems they can cause, keep reading to discover how to get rid of them!

Comparison of bathtub with red water stains and a clean bathtub

How to Get Rid of Red Water Stains

Whether your red water stains come from iron or Serratia marcescens, you can find simple instructions for scrubbing those stains away below. We can also help you find the right water treatment equipment to keep iron from causing those stains.

Unfortunately, water treatment equipment can’t help with stains caused by Serratia marcescens. The best way to combat those stains is with regular cleaning.

Follow the steps below to best defend against red residue from water.

Step 1: Test Your Water

The first step in dealing with water contamination of any kind is to have it tested. An EPA-certified home water test will tell you exactly what contaminants you’re dealing with. Once you know this, you can make an informed decision about how to best treat your water.

Step 2: Clean Iron Stains with Household Remedies

If your test shows that iron is causing your stains, then you can scrub them away with a few different cleaning supplies. For example, applying white vinegar or lemon juice typically works on newer stains. You can also try mixing white vinegar and baking soda if you need a stronger scrub. For older stains, using an industrial-strength cleaner like CLR should do the trick.

Step 3: Clean Serratia Marcescens Stains with Chlorine Bleach

Alternatively, stains caused by Serratia marcescens require a very specific ingredient for removal: chlorine. We recommend applying a chlorine bleach solution to the stains, letting it sit for 10-15 minutes and then scrubbing them away. Just be sure to use gloves and open the windows for plenty of ventilation when applying the bleach, as chlorine is very dangerous.

Step 4: Invest in a Water Softener or Water Filter for Iron Contamination

How do you keep iron from causing red residue again? The answer depends on if the iron is ferrous or ferric. As you’ll recall from above, the easiest way to distinguish between the two is ferrous iron is invisible when poured from the tap, whereas ferric iron makes the water appear rusty.

The best solution for small quantities of ferrous iron is a salt-based water softener. Salt-based softeners remove iron through a process known as ion-exchange. The most trustworthy water softeners on the market are NSF/ANSI 44 certified systems. You can view the certified water softeners we sell at Angel Water at the link below.

Larger amounts of ferrous iron and any amount of ferric iron require water filtration. The device we recommend for this is a reverse osmosis (RO) system. This type of system puts the water through multiple layers of filtration to remove iron and many other contaminants. You can learn more about our NSF/ANSI 58 certified RO systems below.

Need More Help with Water Leaving Red Stains?

As you can see, getting rid of red stains from water for good is possible! It just takes some action on your part to get the ball rolling.

If you need help with any of the steps described above, Angel Water is here for you! We can help you diagnose what’s causing your stains with EPA-certified water testing. Our water treatment specialists can then help you choose the perfect treatment system from our wide selection of quality water filters. And once you’ve made your choice, our licensed plumbers would be happy to install it properly for you!

Our goal is to provide healthier water for Barrington, IL, and the greater Chicagoland region. We also serve West Palm Beach, FL.

Give us a call today at (847) 382-7800 or fill out the form below to talk to an expert and schedule a free consultation!

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