Written by: Gene Fitzgerald // Last Updated: Jul 28, 2023
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.
Reverse osmosis water has very low TDS levels by default.
While that’s the desired effect for most people, sometimes you may want to take things in the opposite direction a little bit.
Increasing the TDS of your reverse osmosis water can make sense in some cases, especially when it comes to personal preferences like taste.
How to increase TDS levels in RO water? Let’s discuss!
Key Takeaways
There are several ways to increase the TDS levels of reverse osmosis water:
So, how can you increase RO water TDS?
There are several ways to increase the TDS level of reverse osmosis water. Most of those are easily accessible, so you should have no problem implementing them in your situation.
Remineralizing your RO filtered water is the best way to increase its TDS levels, as it also comes with various health benefits thanks to the increased consumption of minerals.
Theoretically, you could also increase the TDS of your reverse osmosis water by increasing it at the source. Since reverse osmosis reduces TDS by a certain percentage, usually somewhere around 80 to 99%, increasing the number of dissolved solids in your input water will proportionally increase the TDS level of the output water as well.
However, this doesn’t make much sense for a number of reasons. First, you’ll have to use more resources to increase the TDS level of the feed water, as most of them will get stripped away by the reverse osmosis process. Second, this will put extra strain on your RO membrane. It’s better to simply add minerals as a post-filtration stage instead.
A TDS controller is a device designed to increase the TDS levels of filtered water. It has two inputs and one output. It works in the following way: The input water stream is split into two parts, A and B. Line A is fed into the reverse osmosis system as usual. Line B goes into one input port of the TDS controller without being filtered. The filtered (output) line of the reverse osmosis filter is connected to the other input port of the TDS controller. Internally, the controller mixes the two streams in a fixed proportion, increasing the TDS levels of the output water.
You may have noticed an obvious problem in this setup: You’re mixing unfiltered water with your filtered reverse osmosis water. This carries the risk of reintroducing some contaminants. In some setups, the unfiltered water line (B) is passed through a UV filter before it enters the TDS controller. While this does neutralize microorganisms, it does nothing against other types of contaminants like heavy metals.
Reducing the pressure of your feed water line will increase the TDS levels of your RO filtered water. However, it will also result in more water going to waste due to the way a reverse osmosis system works. In addition, you will notice a decline in the quality of your filtered water, as some contaminants will make their way into it – not a good method!
Higher feed water temperatures are associated with a decreased salt rejection rate. And while that’s certainly one way to increase your TDS levels, it’s far from optimal. It causes the membrane to expand, allowing some contaminants to potentially pass through, and possibly decreasing the lifespan of the membrane due to the constant shrinking and expanding.
But why would you want to increase the TDS levels of your reverse osmosis water in the first place? The whole point of reverse osmosis is to bring those levels down, right?
There are several good reasons for this.
The ideal TDS level of reverse osmosis water is somewhere between 10 and 50. While going above 50 is still okay in terms of drinking water quality – up to around 300, in fact – it could indicate problems with the operation of your reverse osmosis system. That’s why it’s recommended to regularly test your system to ensure its optimal performance.
If you have any questions about increasing TDS in RO water please don’t hesitate to leave a comment below!
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.