Why Zero Water Smells like Fish? (Best Tips To Remove it)

A fishy smell from zero water is a problem that some people face. There are multiple reasons why zero water can smell like fish. Most of the time, it is because the water is not filtered correctly. Therefore some contaminants and impurities are left in water.

These contaminants can cause the water to smell like fish. For this reason, you must have a high-quality water filter.

Another reason why zero water smells like fish is because of the chemical known as Trimethylamine. This chemical has a rotten fish-like smell that can cause it to smell fishy when mixed in water.

There are some solutions to this problem that can be done possibly. However, before looking for the solutions, you first understand what causes the fishy smell and why it happens.

Why Does Zero Water Smell Like Fish?

Mostly the filters make use of carbon fibres for cleaning the water. The carbon filters have granules that are porous and can absorb contaminants. However, some of the contaminants still left in the water can make the water fishy.

ZeroWater filters are popular because these filters use a different technology for removing impurities from water. The process of cleaning water involves five different stages data-preserver-spaces=”true”> for removing the dissolved minerals.

Before looking for the reasons that cause the zero water smell fishy, it is essential to understand the working of zero water filters. Moreover, it is also essential to understand the five-stage process for cleaning water.

Five Stage System of ZeroWater Filters

In this five-stage system, the first stage is the filtration stage. During this stage, the water is passed through a coarse filter screen. The coarse filter screen has an infusing micro carbon cloth of high quality.

During this stage, the sediments and other particles are filtered from water and the filtered water moves to the second stage.

The second stage can be called the secondary filtration system. In the 2nd stage, the water has to pass from a foam distributor. The foam distributor can spread the water on the filter. As a result, more contaminants are removed from the water.

In the third stage, the ZeroWater filter uses oxidation and carbon. A multiple layer system is involved in this process. Carbon is capable of removing pollutants from filtered water.

Moreover, the oxidation-reduction process further makes sure that there are no metals or chlorine in the water. The fourth stage involves the ion exchange method, which is why most people prefer ZeroWater filters.

The ion exchange method ensures that there is no ion left in the water, and the water is purified completely. The last stage is the final stage, where an ultra-fine screen is used. It is combined with the non-woven membrane layers.

This membrane gives a final blow to any of the contaminants if left in the water. After this last step, the water you get is in perfect condition.

Related Article: Does ZeroWater Filter Remove Bacteria?

Anion Resins Also Cause Fishy Smell In ZeroWater Filter

Anion Resins Also Cause Fishy Smell In ZeroWater Filter

There can be several reasons for the fishy smell coming out from zero water. The most common reason for the fishy smell in ZeroWater filters is the anion resins left in water.

The ion exchange method works in the filter so that the anion and cation resins extract impurities and contaminants from water.

Cations and anions contain hydroxide and hydrogen, which, when combined, form pure water. When all hydroxide and hydrogen is used, only the anion resins are left, which release a chemical known as Trimethylamine.

Trimethylamine has a rotten fish odor which also makes the water smell fishy. Moreover, the fishy smell may also be coming from your tap. If it is coming from the tap, it can mainly be due to the mineral deposits in the tap.

One of the reasons for the fishy smell can also be the oxidation in water to the facet joint. This oxidized joint allows the sediments and minerals to be deposited in the joint, making the water smell fishy.

Solutions for Removing Fishy Smell from ZeroWater Filter

Anion Resins Also Cause Fishy Smell In ZeroWater Filter

There are multiple solutions for removing this fishy smell from zero water. Some of these solutions are mentioned below.

1- Replacing the ZeroWater Filter

Replacing the ZeroWater filter becomes essential, especially when the filter has purified 20 gallons of water. You should also return the filter when the water quality meter shows a 006 measurement of the filtered water.

You may not even be able to filter 20 gallons of water if the tap water has a rate higher than 300. The higher TDS rate indicates a greater amount of dissolved solids.

You should not delay changing the filter because it can be challenging to wash the Trimethylamine off plastic. Therefore if you delay in replacing the filter, you may have to separate the pitcher.

In this way, you will have to wash the pitcher and spigot several times with the dishwashing soap to remove the smell. After repeating this process several times, dry every part and put it together with the new filter.

2- Do not use Filter with Hot Water

Some research has been done on the degradation of anions. One of these studies has shown that the anions degrade at a faster rate in heat. Moreover, these remain most stable when at room temperature.

Therefore it is best if you do not use hot water in the filter. Also, another suggestion in this regard is to keep the pitcher out of the fridge.

3- Chlorine and Chloramine

Chlorine and chloramine are the two substances that cause the anions to degrade faster, producing Trimethylamine, causing the fishy odour. Not all the clients of ZeroWater filters complain about this issue.

Therefore there might be a possibility that some specific substances in the tap water are causing the degradation of anions.

So if you live in an area where the municipality uses chlorine or chloramine for cleaning the water, then the ZeroWater filter is the wrong filter for you.

4- Filling the Reservoir to Half

Make sure to fill the water reservoir halfway. This solution may not prove as convenient, but the filter can last longer in this way and without any fishy odour.

5- Cleaning Faucet Joints

If the solutions mentioned above are not working for you, the fishy smell may be due to mineral buildup in faucets. These mineral deposits cause the problem. You may have to call an experienced plumber to check the faucets and clean them.

How To Replace the ZeroWater Filter

Replacing the ZeroWater filter is not very difficult. There are just a few simple steps that you need to follow.

  • First of all, you need to remove the lid and then remove the reservoir.
  • After this, you need to unwrap the packaging of the filter. Discard the packaging. Moreover, you may need to screw off the blue colored cap.
  • The silicone rings should also be tight.
  • At the bottom of the reservoir, screw the filter and tight it to seal it completely.
  • It is essential to make sure that you don’t place the filter from above into the reservoir.
  • At last, put the reservoir in the pitcher, fill it to the top, and put the lid back.


We hope you have already figured out why zero water smells like fish. The most common reason for it is the degradation of anions due to the ion exchange process for purifying water.

There are a few things that you need to do before calling a plumber or replacing your filter. To avoid this issue, you can fill the water reservoir halfway so it may work for a longer time without any smell.

You should know how to take care of the ZeroWater filters. Drink quality water for the sake of your health. We hope that our guidelines will assist you in finding a solution for the fishy smell in zero water.


Why does my Zero Water have a Plastic taste?

Sometimes the tap water can taste like plastic. This smell can either be due to the new plastic pipes or the degrading ones. However, if this is not the reason for the scent, you need to wash your filter correctly before using it.

You do not need to wash the filter that you have purchased from ZeroWater. But, if you have purchased the filter from some other manufacturer, it is essential to run about half a gallon of water through the filter before drinking it.

Does your Zero Water has a Sour taste?

The zero water may have a sour taste, and it happens when the filter has been used even after its expiry date. The expiry date means 400 gallons of water for faucet mount filters, whereas 20 gallons for the pitcher.

There is no explanation for this, but it is possibly because of the contaminants and metals that may be stuck in the filters and are now again mixed in the water.

The hydroxide ions are used first in the pitchers, which means only the hydrogen ions are left in water. These hydrogen ions are mixed in water, making it acidic.

Why does Zero Water have a Chlorine like Taste?

Mainly chlorine is used by municipalities for cleaning the tap water. Therefore the tap water may smell like chlorine. However, if it is not the tap water but the filtered water that smells like chlorine, you need to replace your filter.

ZeroWater filters are popular for removing the smell of chlorine from water. Replacing your filter with a ZeroWater filter will solve the problem.

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