Whole House Water Filter Turns Black? Here Is What to Do!

This page may contain affiliate links. If you buy a product or service through such a link we earn a commission at no extra cost to you. Learn more.

If your whole house water filter has turned black, it’s not usually something to worry about. However, it’s always safer to assume it’s a serious concern, as harmful contaminants may be involved.

Depending on the severity, you may need to call a professional or replace your whole house water filter – but knowing why it has turned black in the first place can help you decide what to do next.

In this guide, we will discuss the different causes for a whole house water filter turning black and how to find the culprit. Let’s get started!

Key Takeaways

If you whole house water filter turns black:

  • Get your water tested to figure out the culprit. It may be iron, manganese, or black sediment.
  • Check your entire filter setup. A carbon filter may be leaking. Or, it might simply be time to replace the black filter.
  • Check your pipes and water heater for signs of corrosion and rust.
  • The issue may be caused by a new or collapsed well.
  • Have a professional check your septic system. It may release contaminants into your well water.

Causes for a Whole House Water Filter Turning Black

There are many factors to why your whole house water turned black. Consider the following:


One of the most common causes for a whole house water filter turning black is iron or rust in your water. This can be due to old pipes in your home or well water that contains high levels of iron.


Manganese is another common cause of black water filters. Like iron, it can be present in well water. High concentrations of manganese may be harmful as it could lead to health problems.

Black Sediment

If you are dealing with well water, you may have black sediment problems. Black sediment could either be these two things:

Sand and Silt

For well water, it is common for there to be sand and silt since the water runs over rocks and soil. This can build up over time and cause your filter to turn black. Sand and silt are not particularly harmful, but they can decrease your water quality.

Organic Matter

Sometimes organic matter, like algae or bacteria, may find its way into your well water and decompose. Over time, this could clog up your pipes and whole house water filter and cause the water to appear dirty/black.

black whole house water filter

Activated Carbon

If your whole house water filter uses activated carbon, the black color is most likely due to the carbon itself and is not a cause for concern. Over time, the carbon will become saturated with impurities and will need to be replaced.

Mold/Mildew Growth

Black water filters are sometimes accompanied by a musty smell. If that’s the case for you, it could be due to mold or mildew growth caused by high humidity levels or a lack of ventilation in your home.

New Well

Newly dug wells can make your water appear dirty or discolored for a while. The black particles could be minerals or sediments that have been drilled up during your well’s construction. It may be a while for these particles to clear up, but they are not a serious matter.

Collapsed Well

Heavy rain or an earthquake may cause your well to collapse, which can allow sediment and other contaminants to enter your water supply. This can clog your whole house water filter and turn it black.

Failing Septic System

A failing septic system can also cause your whole house water filter to turn black. The septic tank can leak sewage into the groundwater, which will then be filtered through your whole house water filter.

Finding the Culprit

To ensure fewer instances where your whole house filter turns black, it’s best to address the root causes. Here are things you can do to find the culprit:

Get Your Water Tested

A good first move to figure out the culprit is to get your water tested. There are different types of water tests, but you’ll want to specifically test for iron and manganese. These minerals are often the culprits behind black water filters.

You can either have a professional come out and test your water, or you can purchase a do-it-yourself testing kit from a hardware store.

Check Your Pipes and Water Heater

Check your pipes and water heater for any signs of corrosion. Since pipes are usually constructed with iron, they may rust or corrode over time. Make sure to have them inspected and repaired if needed.

Check Your Filter Setup

If you have a carbon filter as part of your whole house water filtration system, then it’s possible that the filter just needs to be replaced. To check, take a look at your carbon filter and see if it’s leaking filter media or if there’s a lot of build-up on it. If so, then it’s time for a new filter.

Check Your Well

If you have a well, check to see if the water level has lowered. This could be a sign that your well is running low on water and causing sediments to enter your home’s water supply.

Check Your Septic System

A malfunctioning septic system can release contaminants into your water supply, which will turn your whole house water filter black. You should have your septic system checked by a professional at least once a year to ensure that it is functioning properly.

How to Maintain a Black Whole House Water Filter?

The best thing to do when your whole house water filter turns black is to replace it. That way, your water quality may improve, and you can prevent any health hazards. But if you have successfully determined the cause to be not harmful, here are a few things you can do to help maintain your whole house water filter:

  • If your water filter is clogged, replace the pre-filter.
  • If there is too much sediment in your water, backwash the system more often if possible.
  • You can also try flushing the system with clean water to see if that helps clear out the blackness.

whole house water filter cartridges of different sizes

How to Prevent Your Whole House Water Filter from Getting Black

In some cases, your whole house water filter turning black may be unavoidable. But there are measures you can take to ensure these instances don’t happen as frequently.

  • Change your whole house water filter every 3 to 6 months, depending on usage and water quality.
  • If you have well water, have it tested regularly.
  • Have your pipes and septic system inspected regularly.
  • Form a routine of cleaning your water filtration system regularly to avoid any contaminant build-up.

With these precautions in place, you will be far less likely to encounter a blackened and dangerous whole house filter.

If you have any questions about why your whole house water filter gets black please don’t hesitate to leave a comment below!

About the Author Alexandra Uta

Alex is a content writer with an affinity for research and a methodical attention to detail. Since 2020, she has fully immersed herself into the home water treatment industry only to become an expert herself. Alex has been using water filters and similar products for years which has gained her lots of hands-on experience.
Learn more about .


Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment: