What is TDS?

TDS is an abbreviation for “total dissolved solids,” a term used to describe inorganic matter like minerals, metals, and salts that can end up in your water supply.

The good news is that TDS generally isn’t a health concern in your drinking water. However, it’s not without its problems. A high TDS level can impact your water’s taste, your budget and even your hair and skin. On top of that, you may not even realize your tap water contains elevated TDS until after these issues occur.

Fortunately, you don’t have to rely on guesswork. Here’s everything you need to know about TDS in water — from identifying to addressing it.

Understanding Total Dissolved Solids

The solids in TDS are often one or more of these substances:

• Calcium
• Magnesium
• Sodium
• Chloride
• Some metals like iron and manganese
• Carbonates
• Nitrates

These substances can be found just about everywhere, including:

• Rocks, bedrock and soil: As water contacts these naturally occurring formations, it dissolves the minerals that form them — especially limestone (calcium carbonate) and gypsum (magnesium sulfate). Deep water sources like wells tend to have higher TDS levels than regions that rely on surface water supplies., like reservoirs.
• Seawater: Well water near coastal regions may have a high TDS level. That’s because seawater has a high salt and mineral content and may infiltrate ground water sources increasing the TDS levels.
• Human activity: Everything from mining and agriculture to everyday water use can add to the TDS concentration. Even the salts used for icy roads can increase the TDS of a water supply.

Any solid from the list can contribute to the TDS level, and every water supply likely contains several different forms. One of the problems with interpreting TDS is that there’s no indication which minerals and salts maybe present in which amounts, so this name is more of a broad categorization than a single contaminant.

It’s also important to note that many of these dissolved solids are perfectly fine on their own. For instance, calcium and magnesium are common in some bottled mineral waters . However, on the other hand, these same minerals cause hard water, which creates significant issues for your home.

That’s why it’s difficult to call TDS a contaminant in tap or drinking water. By itself, a TDS level is just a measurement of the dissolved solids in your water — not a statement on whether those substances are “good” or “bad.”

However, that complicates things. A TDS concentration is expressed as a whole and generally isn’t broken down based on which substances are present. For example, if you were to use a home TDS tester, you’d get a result in parts per million, or ppm — but 500 ppm doesn’t tell you what those parts are, where they came from or whether you need a particular kind of water filtration.

For this reason, it’s important to understand exactly what comprises TDS and how it may impact your drinking water.

Why Total Dissolved Solids Matter

Because water moves through nature as part of the hydrological cycle, a certain TDS level is expected — and nothing to be concerned about in many cases. Varying TDS levels in water can have certain undesirable effects, including:

• Taste: Water’s taste can change depending on the mineral content or other TDS components. For example, too much chloride can make water taste salty, while sulfate is bitter and bicarbonate is astringent. On the other hand, low TDS can make water taste flat.
• Corrosion: High TDS concentration can corrode distribution systems, pipes, water-using appliances and more.
  Scaling: TDS also contributes to scaling or mineral buildup inside pipes and water-using appliances, reducing water pressure and service life.
• Cloth deterioration: The more often you wash clothes and other cloth material in water with high TDS, the abrasion from these minerals cause these items to deteriorate faster.
• Comfort: Elevated TDS levels may lead to issues like dry skin, hair and nails.
• Cleaning: TDS can cause mineral buildup, soap spots and even decreased soap lathering and cleaning product effectiveness, making cleaning even more of a chore.

Do you have water problems like these? Try our Water Solutions Finder.

Some of these are similar to the issues caused by hard water, which is the result of too much calcium and magnesium in your water supply. That means you may need both a water filtration solution and a water softening system to address everything.

Is TDS Safe?

Both the Environmental Protection Agency and Guidelines for Canadian Drinking Water Quality maintain aesthetic limits on TDS levels, which refer to problems like odd tastes and odors. These organizations don’t set primary standards for TDS, which generally means the substance in question isn’t a significant risk to human health. However, some contaminants that can be part of TDS — such as nitrate and sodium — could potentially cause negative health effects and require further water testing.

Sources of TDS in Drinking Water

With so many possible meanings, even a low TDS level can lead to some big questions. One of the most important is this: “Where do these solids come from in the first place?”

Natural vs. Man-made

Natural vs. man-made substances aren’t classified in the same way as organic and inorganic solids. Instead, the focus is on whether the substance was introduced to the water supply from the natural environment or human activity.

This can be difficult to identify. After all, humans and nature interact in all kinds of ways. For example, road salt can be washed away by rain or snowmelt and carried to a water system’s main source by streams — but that doesn’t mean the salts themselves are now considered a natural substance.
The main focus here is what these solids could be carrying with them. Salt from rocks and minerals may introduce one problem to the water supply, but salt from road treatments could have other additives not found in nature.

However, TDS concentration measurements can’t identify sources. These tests will just tell you the overall TDS level — not whether each substance was introduced by nature itself or runoff, soil contamination and industrial discharge. That means the “natural vs. man-made” classification is generally more helpful for understanding possibilities than for making final decisions about your water quality.

TDS Water Testing

It’s possible to use a “TDS tester” or “TDS meter” on your own and get a relatively accurate TDS level. However, the results may not be as comprehensive as you need — as the components of TDS won’t be identified.

Instead, consider a professional water test. In 30 minutes or less, a local water expert can provide specific, detailed information about your home’s water quality. And they won’t stop at TDS levels — these tests also cover water hardness and potential contaminants like iron and chlorine. You’ll also get personalized recommendations to help you choose the right water solutions for your unique needs.

Water Solutions: Total Dissolved Solids and Beyond

While TDS may not be a health concern, it can certainly impact the taste of your water. If calcium and magnesium are present in high levels, TDS can lead to hard water issues, too.

That’s why it’s smart to consider two kinds of water solutions:

Reverse Osmosis Drinking Water Filtration

Reverse osmosis filtration, sometimes called RO, targets a broad range of contaminants and water problems. These systems don’t just address TDS; they can also reduce lead, copper, bacteria, viruses and even emerging contaminants like PFAS (also known as forever chemicals). That means RO water is cleaner, clearer and more refreshing.

On top of that, there’s no need to worry about removing flavorful minerals. Some RO systems have an optional mineral cartridge that gives you control over the taste of your drinking water.

You can also choose a smart RO system, which comes with a host of versatile, helpful features. For example, you can connect your filtration system to your phone to get updates and notifications — and you can even track your water usage and conservation goals.

Water Softening

For hard water issues like limescale, soap scum and mineral buildup, you’ll need a water softener. These systems trap calcium and magnesium using unique resin beads that act like magnets. Once the hard minerals are “stuck” to the beads, soft water flows out to every tap in your home. Meanwhile, the beads are rinsed with a brine solution in a process called regeneration, which is often based on water usage.

If you have hard water and other issues, you can also use a softener and a filtration system together; one doesn’t cancel out the other. However, it’s important to note that these two systems do separate things. The processes are entirely different. While certain softeners have built-in systems for filtering chlorine or iron, these are special cases — and even then, you may still want an RO solution for more comprehensive filtration of drinking water.

Improve Your Water Quality Today

There’s a lot to know about TDS — what it really means, where it comes from, how and when it gets into your water supply, what its impacts look like and more. Despite all that, TDS is generally more of an aesthetic concern than a health issue, so there’s no need to panic. Instead, get all the facts about your home’s water quality and make informed decisions from there.

Schedule your free, in-home water test and consultation to get started.