By Rehan Iqbal
We all want to believe that the water we drink is safe and clean. After all, when you live in a developed country like the US, you expect the authorities to test your water and ensure that there are no contaminates that would harm you or your family.
Then you see a report in the news about urban water contamination. We all remember the Flint saga and the devastation it caused. If you rely on well water, there is no certainty as to what is in the water unless you test it.
It is only natural that you want to check that your water is not contaminated. A really quick, inexpensive, and easy solution seems to be a TDS meter or TDS tester. I’ve seen them advertised from as little as $10. If you believe the manufacturer’s claims, it seems like the perfect way to test your water to determine if it is safe.
Before you buy one of these water testing devices, get the facts. How effective is a TDS meter? Does a “Healthy” TDS reading mean that your water is 100% safe to drink? We’ve investigated the matter and I’m going to share this information with you, so that you can make an informed decision about testing your water and ensuring that is safe.
What is TDS?
Total dissolved solids (TDS) are minerals that are found in liquids, usually water. When rainwater comes into contact with the ground and rocks, it collects minerals as it flows and seeps into the ground. The most common minerals found in water are calcium, magnesium, and sodium. Though there are much more dangerous TDS that can occur in some water sources like lead and arsenic.
Apart from the natural process of accumulating TDS through runoff and leaching, tap water can have increased mineral levels derived from other sources.
Where Do TDS Come From?
Are TDS Bad For You?
While there are no health risks directly associated with most TDS, high levels of minerals in water are not exactly good for you. In high enough quantities, some can be a serious health risk.
Hard minerals are common in water supplies in many parts of the US. The perfect amount of hard minerals in the water is around 500 Parts per Million (PPM). TDS in this range gives the water a refreshing natural taste and the minerals are of a sufficient level to be considered healthy. Many minerals, like calcium, potassium, and magnesium are essential for good health, provided they are consumed in the correct doses. Too much of any mineral can be bad for you. Above 1,000 PPM is considered unhealthy. For water with more 2,000 PPM, a filtration system is essential.
Apart from affecting the taste and its health implications, hard water has other negative effects. It can cause laundry to be hard and have white spots. It also leaves an unsightly film on dishes. Hard minerals, like calcium, cause limescale which can block your pipes and damage appliances like washing machines, dishwashers, and coffeemakers.
If you live in a hard water area, a TDS meter will let you know what level of dissolved salts are in the water. For this purpose, it is a pretty handy device. However, a TDS tester will not tell you what minerals are in the water or their individual concentrations. You won’t know, for instance, exactly how many PPM of calcium or magnesium is in the water. A TDS meter also does not test for other contaminants in the water.
How Does a TDS Meter Work?
The principle behind a basic TDS tester is quite simple. Minerals are conductive. This means that when an electric current is passed through the water, the dissolved salts will conduct the electricity. A TDS meter measures the conductivity of the water by sending an electric current through it.
Based on how much current is conducted, the meter will tell you if the water is good or bad. Basically, the TDS meter informs you whether the amount of TDS in your water is healthy or unhealthy.
Cheap TDS meters measure minerals in parts per million (PPM). This is okay for many of the less toxic minerals found in water. However, the most harmful minerals like lead, arsenic, chromium-6, and some others are dangerous in very small quantities, requiring testing down to parts per billion (PPB).
Some expensive meters will provide more detailed information, but they don’t supply a comprehensive overview of the exact mineral content. Nor do they test for non-conductive contaminants. For this information, more sophisticated laboratory equipment is required.
When it comes down to it, a TDS meter is a very rudimentary device for detecting the presence of minerals in water.
How to Use a TDS Meter
A TDS meter is as simple to use as the information it provides. It is small device that can be held with two fingers. All you need to do is witch it on and immerse a probe into a glass of water. The amount of TDS (usually calculated as PPM) is displayed on a small LCD screen.
Generally, the meter has a “clear” button which will reset the device for further testing.
Is a TDS Meter Useful?
I suppose if you want to test well water for minerals, and that is your only objective, a TDS meter is worthwhile. However, it only gives you a small part of the greater picture. There are many contaminants that can be found in water. Most of them are a lot more harmful than the minerals measured by a TDS meter.
Toxins found in industrial waste are numerous, many of which can cause serious health problems. Pathogens, VOCs, pesticides, herbicides, and chemicals like chlorine and fluoride are fairly common in water supplies. All of these contaminants can affect your health or the taste of your water.
To determine if your water is safe to drink, you need a much more comprehensive water analysis than what a TDS meter can provide. The EPA requires that all municipal water be tested, and that the information be public knowledge. You can obtain fairly comprehensive water testing data from your local water supply authority. This information is usually posted on their website.
Though, even municipal water testing is not 100% comprehensive as they are only required to test for certain contaminants. Although this is generally satisfactory for determining if city water is healthy, municipal testing may not reveal all the potential risks or factors that could affect the taste and odor of your water.
Because municipal water is tested at the point of supply, it cannot detect contamination that results from broken pipes and other damaged water infrastructure. Some people prefer to have their water independently tested by a laboratory for a truly accurate assessment of the quality of their tap water. Though, most folks are find the official water testing to be quite satisfactory.
Even a cursory observation can help you determine if the water in your home is not the best. If your water is cloudy, has a bad odor, or doesn’t taste good can help you decide if you need to filter the water that you drink.
What Should You Do About Water With High TDS Levels?
Hard water is a common problem affecting many areas in the US. Most of the North American continent was once a seabed. This means that large deposits of minerals lie beneath the surface and these leech into ground water. Many American homes have a problem with hard water and want an effective solution to remove hard minerals from their water.
Reverse Osmosis (RO) is the best way to remove most TDS. An RO filter works by forcing pressurized water through a dense membrane which traps salts and other solids as small as 0.5 micron. Apart from removing TDS, most pathogens and many harmful chemicals are also removed.
Activated carbon filters are generally used as part of an RO filtration system, helping eliminate bad odors and improving the appearance of the water. They are very effective at removing chlorine which is a common disinfectant used in municipal water treatment plants.
If the water in your home is particularly hard, you should consider a water softener or water ionizer. Generally, a water softening filter utilizes an ion exchange resin. The resin is ionically charged to attract hard minerals. The minerals bond to the resin beads, allowing only soft water to pass through the filter.
The downside to using an ion exchange resin filter is that they tend to waste water. In order to remain effective, the resin needs to discharge the heavy metals that they have accumulated. The resin regeneration process involves using water to flush the minerals from the filter and sending them down the drain. This ensures that the resin does not become saturated with minerals that would render them ineffective.
Electrolysis can also be used to remove hard minerals. This uses an electrically charged cathode to create an ionic charge within the water. The hard minerals are attracted by the charge and are thereby removed, leaving the water soft and ready for use.
There can be no doubt that TDS in water is a genuine problem for many households. Given this threat, it is understandable that you may want to test your water to see if excessive minerals are a danger to your health.
Personally, I don’t feel that a cheap TDS meter provides the correct information to make an informed decision. It will give you a fairly basic indication that there are minerals in the water, measured in PPM. You don’t know what these minerals are, and it is not accurate enough to detect small amounts of potentially lethal metals.
A TDS meter can make for a cool party trick, showing your friends and family that the water you’re offering them is safe. Though this information is misleading. It only provides a cursory overview of the basic mineral content and does not test for the myriad of other contaminants that could be potentially dangerous.
While laboratory testing is more expensive than a common TDS tester, it is much more comprehensive and accurate. If you feel the need to test your water for contaminants, it is worth spending the extra money to have it done right.
Most people have come to realize that a water filter for their home is beneficial for many reasons. In the end, it doesn’t matter if you test your water or not. Installing a quality water filtration system will ensure that you have clean safe water, regardless of what contaminants are present in your tap water.