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TDS in Water

By April 15, 2019November 29th, 2020No Comments

We’ve gathered all the information we could find and created this blog to be your one-stop shop for understanding TDS. Enjoy!

First things first, let’s establish what TDS is.

TDS stands for Total Dissolved Solids. What are dissolved solids? Any minerals, salts, metals, cations or anions that are dissolved in water. These contaminants are present in the water after the normal filtration process.

How do you know if you have moderate or high TDS in your water? You may notice deposits, colored water, staining and/or a salty taste. These are not harmful, but rather noticeable aesthetic (such as smell, taste or color) effects when the TDS is above 500 ppm.

When you invest in a fridge, pitcher or faucet filter, you expect it to remove TDS. Right? Unfortunately, most filters are not designed to reduce TDS. The most popular way to reduce TDS from your water is to invest in a Reverse Osmosis Water Filter System.

Now that we’ve established what TDS is, let’s talk about how to measure TDS.

One of the easiest ways to test TDS in your water is by using a TDS meter. A TDS meter is a small hand-held device that estimates the TDS level by measuring the electrical conductivity of the particles in the water.

What does a TDS meter not measure? A TDS meter reading is NOT a measure of overall water quality. Healthy minerals like potassium, magnesium, and calcium can cause your reading to spike. TDS meters do not directly measure heavy metals like lead or other contaminants like pesticides, pharmaceuticals or hexavalent chromium.

Are you wondering if you should invest in a TDS meter? While the decision is ultimately up to you, it is not necessary to have a TDS meter. If you want to know what is in your water, we recommend testing your water with a Water Test Kit. Water Test Kits will tell you exactly what is in your water—including dissolved solids.


Are you concerned about TDS in your water? Here are a few ways you can reduce TDS in your water:

Invest in a Reverse Osmosis Filter System

Reverse Osmosis is the most popular way to remove TDS from your water. Reverse osmosis forces water under pressure, through a synthetic membrane. The membrane will only allow molecules smaller than 0.0001 microns to pass through it. Molecules of dissolved metals and salts are large compared to the water molecules, so the water that passes through the membrane leaves the metals and salts particles behind.


Distilling water involves boiling water to produce water vapor. The water vapor then rises to a cool surface and then condensed back into the liquid form. Dissolved salts are unable to vaporize and remain in the boiling solution.


This process involves water passing through a positive and negative electrode. Ion selective membranes cause the positive ions to separate from water and move towards the negative electrode. The result? De-ionized water with high purity. However, before this can happen, the water must first be passed through a reverse osmosis unit to remove the non-ionic organic contaminants.

Common Questions about TDS in Water:

Q: After I installed my filter, the TDS was high, why did this happen?

A: Carbon filters can raise TDS. This is usually more prominent right after you install it. Once you flush your filter, TDS will drop back down. This momentary increase is not harmful.

Q: I used a TDS meter and the read was positive. Is there something wrong with my water filter?

A: Nope! There’s nothing wrong with your filter. A TDS meter is a broad test used to determine levels of TDS in liquid. Most meters measure inorganic and organic substances in molecular, ionized or micro-granular suspended form. Common TDS substances include calcium, phosphates, nitrates, sodium, potassium, and chloride. When water is void of TDS can be flat, have an unpleasant taste and could be lacking in important and healthy minerals your body needs. If you think that there is something wrong with your filter, you will need to do a test that focuses on the contaminants that the filter is supposed to remove. A TDS meter tests too broad of range and will not give you an accurate reading on whether your water is functioning as it should.

Q: I used a TDS meter and the results were way higher after the water was filtered. Is this normal?

A: Depending on the type of filter media that is being used, the TDS reading can be much higher after the water is filtered. Sometimes carbon filter media can release carbon fines during initial use. These harmless particles can cause your TDS reading to be higher. Once the filter is properly flushed, TDS will decrease, but if you have a carbon filter, you will consistently see higher TDS readings. Using a TDS meter to test your filtered water is not a good measure for whether your filter is working or not.  

Why is it important to measure and remove TDS?

TDS does not present a risk to human health, the U.S. EPA has not set a mandatory TDS limit, but suggests a maximum level of500 ppm. At or above this level, consumers may notice deposits, colored water, staining and/or a salty taste. These are not harmful, but rather noticeable aesthetic (such as smell, taste or color) effects when the TDS is above 500 ppm.

Water Hardness

If you have hard water, you may have high levels of TDS in your water. If you notice dry hair, spots on kitchen utensils after they are washed, or regularly occurring toilet stains, these are indicators that you have hard water in your home. Hard water is more specific to dissolved calcium and magnesium in the water. This is measured differently than TDS.

Pools and Spas

High levels of TDS in water can become a huge problem for pool and spa owners. TDS can be the cause of constant maintenance.

The point is, the purer you water is, the healthier you and your family will be. Find exactly what you need to create a healthier environment in your home by shopping at is a replacement water and air filter company located in the United States. The views and opinions contained herein are solely those of the original author and do not represent Eco Blue Life or its affiliates. This article was originally published on  
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