Reverse Osmosis Water Smells Fishy? Here’s What to Do!
Written by: Gene Fitzgerald // Last Updated: Aug 8, 2023
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One of the main benefits of reverse osmosis as a water filtration method is its thoroughness. Pretty much nothing else comes close to the capabilities of a reverse osmosis system. The filtration effects are usually noticeable not just in water tests, but through other factors, like the removal of any tastes or odors from the water.
Which is why noticing any kind of smell coming from your reverse osmosis water is usually a bad sign – especially when it comes to particular smells like fish-like odors.
Your reverse osmosis water smells fishy? Here’s what to do!
Contents
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Key Takeaways
- A fishy smell is always a cause for concern when it comes to reverse osmosis water.
- It’s usually caused by one of main four factors: barium, cadmium, chloramine, and algae
- All of those problems can be addressed in different ways:
- Flushing your pipes.
- Changing your filter elements.
- Adding carbon filtration.
- Chlorinate your water supply.
- Using aeration.
- Discussing the problem with your water utility.
4 Reasons: Why Does My Reverse Osmosis Water Smell Fishy?
When your reverse osmosis water smells like fish, this can usually be traced to one of four main causes – barium, cadmium, chloramine, or algae. Note that those are not mutually exclusive – just because you’ve detected one of those doesn’t mean you should stop your investigation there. You need to exhaust all options to ensure that the smell won’t return.
1. Natural Occurring Barium in the Water
Barium is a metal that can produce a fishy smell in water. It often finds its way into water sources through natural means, and it’s even capable of bypassing the membrane of a reverse osmosis system to some extent. This makes it the number one suspect in cases of foul-smelling reverse osmosis water. Normally, your water should be treated for barium at the source – but it’s possible that you might have local fluctuations.
2. Cadmium
The same goes for cadmium. If you live near an industrial zone or farming lands, it’s possible that you’re dealing with elevated levels of cadmium in your water. It’s commonly found in various types of industrial waste, and is also used in some fertilizers.
Just like barium, a reverse osmosis membrane is very well capable of removing cadmium, but only to a certain extent.
3. Chloramine
Chloramine is a disinfectant which is used to treat water for various contaminants. Ironically, it can also cause a foul smell in water that’s treated with it, especially when the chemical is used in high quantities.
4. Algae
It’s also possible that you’re dealing with excessive algae growth. This is especially common when sourcing your water from still reservoirs exposed to sunlight for prolonged periods of time. That’s why modern reservoirs are usually partially or completely covered, or use alternative means to keep sunlight out. That’s not always the case though, and it’s possible that you’ve got a lot of algae growing somewhere in the vicinity of your water filter.
What to Do About the Fishy Smell of RO Water
Identifying the root cause of the problem is only one part of the equation. You must also know how to address the situation. Sometimes, it might be possible to fix the problem once and for all – but in other cases, you’ll have to perform regular maintenance on your plumbing or filtration system to keep the issue from reoccurring.
Flush Your Pipes
One of the simplest things you can do is to flush your pipes regularly. Various materials can build up inside them, especially algae, potentially leading to the development of foul or fishy smells. You might have to do this quite often, depending on the state of your plumbing.
Change Your RO Filters
Your reverse osmosis membrane, or any of the other filters used in the system, may be up for replacement. You need to remember to maintain your system in good condition by regularly replacing all filters when their time is up. If you have a more complex setup with multiple pre- and post-filters, it’s a good idea to keep a calendar so you don’t forget anything.
Using an old RO membrane could result in some barium or cadmium remaining in the water.
Chloramine can be removed using activated or catalytic carbon.
Add a Carbon Post-Filter
If you’re not using a carbon post-filter in your reverse osmosis system, you should definitely consider adding one. For many people, it’s a default stage that should always be present in a complete reverse osmosis setup.
A carbon post-filter can do a great job at eliminating various smells, including fishy odors.
Further Reading:
Chlorinate
Increasing the chlorine level of your water can be helpful when dealing with certain contaminants, like algae. This should be done in a careful, measured way, to ensure that you don’t overdo it and potentially shift your water into another unpleasant state.
Call Your Water Utility
Have you considered calling your water utility company? They might be aware of an ongoing issue, in which case they can at least put your mind at ease. Otherwise, they can send out an inspection crew in an attempt to figure out what’s going on with your water supply.
Use Aeration
An aeration system is another useful tool for dealing with fishy-smelling water.
It allows any dissolved gases to escape, including bad smell.
If you have any thoughts about the question, why does my RO water smell fishy, please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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