Algae in Whole House Water Filter? Do This!

Author: Jason Hollow - Published: 2022/10/20 - Updated: 2022/12/22

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It is quite common for whole house water filters to suffer from algae problems.

Though algae in a water filter are not a major issue, it can affect how the filtered water tastes and smells. Furthermore, increased exposure to algae can be harmful, causing a wide range of health effects.

Simply put, when it comes to algae in whole house filters, you want to avoid it at all costs. If you aren’t sure how to deal with it, we can help.

In this article, you will learn why algae grow in your whole house water filter, how to deal with them, and how to prevent algae growth from happening again in the future.

So, here is our guide on algae in whole house water filters!


  1. Disassemble the whole house water filter system and remove the housings along with the filter cartridges.
  2. Use a dishwashing detergent and warm water to clean the housings thoroughly. Afterward, wash and rinse with clean water.
  3. As for the filter cartridges, NEVER use detergent on them. Instead, rinse and wash them through flowing water. If the problem persists, it may be time to replace them.
  4. Put everything carefully back together and ensure a tight fit and no leaks.

Additional tips to prevent algae from growing in your whole house filter:

  • Regular maintenance goes a long way in keeping your system algae-free.
  • Remember to install your whole house filter system in a location away from windows and direct sunlight or any other heat source.
  • You might consider installing an additional UV filter to kill off algae spores.

Why Does Algae Grow in a Whole House Water Filter?

Algae is a naturally occurring phenomenon that grow in a variety of forms. They grow through photosynthesis, which means they flourish in situations with plenty of sunlight and mild temperatures.

In addition, some water filtering procedures unintentionally promote algae growth rather than inhibit it. The increased growth occurs because chemical disinfectants that would typically kill algae, such as chlorine, are removed in the filtration process. Furthermore, filtered water sitting in a tank provides the ideal conditions for algae growth, such as low turbidity.

One exception is UV water treatment systems. These, among a few others, kill any germs that cause algae.

How Does Algae Grow?

Algae only need two elements to thrive: water and sunlight[1]. Thus, algae can, and will, bloom if your water filter system is exposed to constant sunlight, even through a window.

This process will be further accelerated if you take water from a source that already contains it, such as a well or a lake.

If your main water line is from the city, it has already been chlorine or chloramine-treated, meaning that algae will be killed before it reaches your whole house water filter. However, algae can still grow after the filtration process if the chlorine is removed because of it.

What Can I Do About Algae in My Whole House Filter?

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Having algae in your whole house water filter while concerning, isn’t the end of the world. All you have to do is clean the system.

This solution, however, will likely only last for a short period of time because algae will grow back if you don’t address the root cause of the issue. After cleaning your filter, you should also consider a more permanent solution.

How to Remove Algae from a Whole House Water Filter

Follow this procedure to clear a whole house filter of algae:

  1. Disassemble the system by removing the housings and filter cartridges.
  2. Remove algae spores from the housings by washing them thoroughly with a dishwashing detergent. After that, rinse thoroughly.
  3. Avoid using detergent on the filter cartridges. Instead, rinse them under running water. If this doesn’t work, it’s best to remove the old filters and replace them.
  4. Reassemble your whole house water filter.

Preventive Measures

You have a few options for preventing future algae growth, such as keeping your filter system as cool and dark as possible, and away from windows and sunshine.

You have to remember that algae love warm temperatures and sunlight!

You could cover your filtration system or windows with a non-transparent material or paint them in an opaque hue.

Cleaning your whole house water filter every six months is also a good idea, though the precise timing will depend on the severity of your algae problem.

You could also add UV treatment to your filtration setup to destroy algae permanently.

Temperature and Installation Location

Warm temperatures are ideal for algae growth. Specifically, the ideal temperature range is between 68 and 86 °F (20 and 30 °C).

If at all possible, locate your system in a cooler environment.

Algae in Well Water

Algae growth is very common in well water. The following factors influence algae growth in wells:

  • Nutrients: Nitrogen and phosphorus promote algae development. These nutrients are typically found in abundance in wells, especially if you reside near agricultural areas.
  • Light: As previously stated, algae require sunshine to flourish. Your well may be indirectly exposed to sunlight depending on its placement.
  • Temperature: Warmer temperatures promote the growth of algae.
  • Stable conditions: Because algae favor low turbulence, still water in wells is ideal for their growth.
  • High pH levels: Alkaline water promotes algae development.
  • Turbidity: Algae love water with low turbidity as particles in the water can impede sunlight from reaching

Combining some of these factors would already provide a favorable environment for algae growth. Well water often contains a combination of several of them.

How to Keep Algae from Growing in Well Water


The only method to prevent algae from growing in well water is to repeatedly treat it, for example, through shock chlorination.

This is the only way to prevent algae from growing inside the well itself.

Finally, if you can address the variables that encourage algae growth in your well, as stated above, you can minimize its potential to thrive.

Can Algae Be Removed from Well Water?

There are several methods for removing algae from your well:

  • Purge your well with a pump at least three full volumes.
  • You can also shock your well by doing the following:
    1. Depending on the diameter and depth of your well, add a suitable amount of chlorine bleach.
    2. Run water into the well with a clean hose, circulating it around.
    3. Turn on your home’s faucets and run the water until you smell chlorine.
    4. Turn off the faucets and wait at least 12 hours for the chlorine solution to work.
    5. Empty the well of all chlorinated water by turning on the faucets of your home and let the water flush out any remaining chlorine.
    6. If you don’t have a chlorine-removal filtration system, boil your water for at least 1 minute before consuming it for the first several days.

Is Algae in Drinking Water Harmful?

Some algae are toxic to humans and animals, and others can create poisonous substances that cause significant illness.

For instance, blue-green algae can cause skin irritation, moderate respiratory difficulties and hay fever-like symptoms.

Toxins produced by blue-green algae can cause symptoms such as vomiting, diarrhea, fever and headaches when consumed.


Finding traces of algae in your whole house water filter or well water isn’t necessarily a huge problem, or even an uncommon one. However, it is something you’ll want to deal with as soon as possible, as letting it fester can result in actual health issues down the line.

Your filter’s location and temperature are factors that can lead to algae growth, so try to avoid locations with warm temperatures or a lot of sunlight.

If you need to get rid of the algae, you can do so through chemical treatment, like shock chlorination, or by installing a water purifier that deals with algae specifically, like a UV system.

Further Reading


Meet Jason Hollow

Jason Hollow Jason is the founder of Water Masterz and head of content creation. After six years in the industry, he has tremendous knowledge and first-hand experience on all things related to water treatment.

His credo: Not a single American should have to drink unhealthy water at home.

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