Water testing test kit dipping in water with black background

What is the Best pH Level for Drinking Water?

Measuring the pH of drinking water not only tells you how acidic or non-acidic (basic) it is, but also its toxicity.

Many people extoll the virtues of alkaline water with higher pH levels, but a low pH level when toxic metals are present could indicate that the water is not suitable for human consumption. Understanding how the pH scale works and what each level means will help you choose the best drinking water and avoid water that will likely make you sick.

The pH level of the water you drink affects the overall pH level of your whole body. Generally, hard water has a higher pH than soft water. Read on to learn everything you need to know about water pH and where your drinking water should sit on the scale for the best health benefits. 

The Science Behind pH

At a molecular level, a pH test measures the concentration of free hydrogen and hydroxyl ions in a solution. More free hydrogen ions solutions are acidic, while more hydroxyl solutions are basic. Luckily, you don’t need to understand the finer points of the pH system as long as you have some idea about what the various levels mean.

The pH scale goes from 0 to 14, with 0 indicating the most acidic solutions and 14 the least or most basic solutions. 7 is pure neutral on this scale. Each number represents a ten-fold increase in acidity. Measuring the pH of water doesn’t only indicate the presence of acidic compounds in it. Nutrients like carbon, phosphorus, and nitrogen also impact the pH of water. 

Digital water test

The pH scale is traceable to a set of standard solutions whose pH levels are established by international agreement.

Understanding pH Levels

Liquid with a pH of 2 is 100,000 times more acidic than neutral water that rates a 7. As you can see from the following examples of liquids with their standard pH levels, the pH of a liquid doesn’t always mean a liquid is potable. 

  • 14 – Liquid Drain Cleaner
  • 13 – Bleach
  • 12 – Soapy Water
  • 11 – Ammonia Solution
  • 10 – Milk of Magnesia, Mild Detergent
  • 9 – Baking Soda, Toothpaste, Hand Soap
  • 8 – Eggs, Seawater
  • 7 – Pure Water
  • 6 – Milk, Saliva
  • 5 – Black Coffee, Bananas
  • 4 – Beer, Tomato Juice
  • 3 – Grapefruit, Orange Juice, Soda
  • 2 – Lemon Juice, Vinegar
  • 1 – Stomach Acid
  • 0 – Battery Acid

As you can see, as you decrease from 7 on the pH scale, the items become more acidic. Lower than 2 and above 8, the examples shift from food and water to non-potable solutions that are incredibly harmful if ingested. 

Ideal pH Levels for Drinking Water

The Environmental Protection Agency (EPA) has National Secondary Drinking Water Regulations (NSDWRs) that recommend a pH range of 6.5 – 8.5 for drinking water in the United States. While this inclusion on the secondary regulations means it isn’t enforceable, it’s still a good indicator of what research says should be the ideal pH for water. Ideally, pure drinking water should be at a neutral pH of 7.

Since groundwater and lakes that serve as municipal water supplies tend to have a mineral content from leaching and contact with rocks and soil, the pH of the water is usually a bit off from that neutral pH mark. This higher pH is actually a good thing because it means your body is getting minerals along with the water it needs to keep all its bodily processes plugging along. But just how much can a pH value shift because of its mineral content?

Minerals & pH Levels in the Environment

Many things can affect the pH of natural water sources. High pH water may be a result of industrial discharges, corrosion of alkaline rocks and soil, asphalt production or disposal, lime use, oil and gas brine, industrial landfills, cement manufacturing, soap manufacturing, and limestone gravel roads.

For organizations like the EPA to consider a water source to be transformed into a high pH one from any of these causes, the water must have a higher pH, lower biodiversity, decreased growth or reproduction in animal species, or reduced dissolved oxygen for a prolonged period. The EPA considers a pH value of 9 or above as high for this test.

One of the most common causes for low pH levels is mining. Weathering volcanic rock and a process called acidic deposition – by which pollutants emitted into the air find their way into water sourced via precipitation – also contribute to lower pH levels in the water. You can find out more about the biological impacts of low pH at the EPA website here.

These EPA considerations are mainly aimed at bodies of water that aren’t used for drinking purposes. Their goal is to protect the natural environment even when we don’t rely on it to provide our drinking water. If a source of human drinking water is at risk for high or low pH as described by the EPA, it would be a massive issue. 

water splashing

Minerals & pH Levels in Drinking Water

By and large, the pH rating of most common drinking water systems doesn’t vary much because it is constantly monitored by organizations at the state, national, and even international levels. One of the biggest factors in the differences between pH levels in drinking water is weathering of mineral-rich rocks and soil. Weather and human activity also have an effect.

Municipal districts often measure the pH of their water sources to make sure contaminants aren’t leaching in and affecting the quality of the water. Minerals leaching in might increase the pH somewhat, but not above potable levels. When water has a high mineral content, it’s referred to as hard water. Calcium, phosphorus, magnesium, potassium, and iron are a few examples of minerals you’ll find in hard water. The more minerals, the harder the water. Water hardness is also measured as alkalinity.

Alkalinity of Tap Water Vs. Bottled Water

“Alkaline” stems from the name “alkali,” which describes a certain type of water-soluble ionic salt with a pH higher than 7. When we talk about alkaline water, most people think of brands that use either chemical or natural means to add minerals to their bottled water. The alkalinity of both bottled water and tap water can vary based on whether municipalities or companies used ion exchange technology or soda ash (sodium carbonate) to soften water.

Even if they don’t use these water treatment options, sources of municipal or private water could also have higher amounts of alkali from soil or rock corrosion. Because of these differences, tap water alkalinity varies greatly from place to place. Broadly speaking, you can expect tap water to have a pH of about 7.5 and most bottled water to have a pH of anywhere from 6.5 to 7.5.

What About Alkaline Water?

Normal bottled water has a pH level that hovers just over or barely above neutral on the pH scale. We already mentioned that companies use chemical treatments or other means to ionize their water and make it more alkaline. They usually use big machines called water ionizers that use electrolysis or ionization – processes of splitting water molecules with electricity to increase the pH level or running tap water over titanium and platinum plates to cause ion exchange, respectively.

People make sweeping claims about alkaline water preventing all sorts of health problems, but is it true? Alkaline water usually has a high pH level of 8 or 9. Proponents of its wellness benefits claim it regulates your body’s overall pH levels, prevents cancer, and even slows aging. While many researchers cast doubt on some of those larger claims, there are some indications that drinking alkaline with a pH of 8.8 may have therapeutic benefits for people with acid reflux disease.

Should people without acid reflux disease bother with alkaline water? While alkaline water might help people with high blood pressure, high cholesterol, or diabetes, it can also lead to a condition called metabolic alkalosis and symptoms such as tingling in the extremities, hand tremors, vomiting, nausea, muscle twitching, and general confusion.

With all these possible side effects, drinking alkaline water is not necessary for the majority of people. The occasional bottle of higher-pH water can be helpful for its possible wellness benefits, but you can have a bottle now and then in between glasses of regular water.

Does pH Affect the Taste of Water?

Most people can discern changes in pH level through their sense of taste. Between pH levels of 4 and 5, acidic or tart tastes are apparent. If we go back to our examples of foods and liquids with different pH levels from earlier in this guide, we get a good idea of how much people can taste varying pH levels. 

At level 5 we have black coffee and bananas. Bananas are sweet fruit if you eat them when they’re ripe. Depending on the kind of coffee you use and the method you use to brew it, black coffee isn’t very sour or acidic even when it’s strong. Down at level 4, we have beer and tomato juice, both of which are considerably more tart than either bananas or black coffee. At 3 we have citrus fruits and soda, which is the highest level of sour flavor for some people.

Remember that each of these levels is a ten-fold increase – so in some way, tomato juice is ten times more acidic than black coffee, and grapefruit juice ten times more acidic than beer. That might seem like a strange system of analysis, but the chemistry says it’s true. Tasting things with a pH of 1.5 causes acid reflux to kick in since that’s the same level as our stomach acid. When it comes to water, it’s unlikely your choice of drinking water will make such large leaps in acidity and flavor. 

One study did reveal that alkaline water with a high calcium content was preferred by participants over high-calcium non-alkaline water. When both sets of water had a significantly lower calcium content, the participants preferred the non-alkaline water. The researchers speculated that this was a result of the electrolysis used to alkalize the water reducing the calcium content at higher levels but not at lower levels.

Does pH Affect Hydration Status?

Even if you find that alkaline water suits your taste preference better, it still may not be hydrating you as well. Although some research found that athletes drinking alkalized water before and during high-intensity impact training were better hydrated, it’s not clear that regular people will need to drink water with higher pH levels to stay hydrated.

Drinking more acidic water could help some people drink more water and thus improve their overall hydration, but overdoing it might pose some health risks if your body’s pH level is too high. People with kidney problems or other chronic issues may not be well-suited to alkaline water at all. If you’re having trouble drinking enough water to stay hydrated, consider flavoring your water with lemon to make it a bit more acidic without any of the negative health risks. 

digital ph reader

Digital pH meters are a little more difficult to use than test strips (because they must be properly calibrated and maintained) but they give more accurate readings.

How to Test the pH of Water at Home

People who drink tap water from municipal sources usually don’t need to test the pH of their water. But if you’re noticing reduced water quality or build-up around your water filter or sink, you might have overly acidic water. Hard water can leave behind trace elements like calcium bicarbonate on dishes, clothes, and sinks. Testing pH can help identify whether there is more in your tap water than you’d like. 

Many people also rely on well water or just want to make sure their filtration system is working properly. Rusty red, white, or blue discoloration around these systems indicates corrosion caused by acidic water. No matter what kind of water system you have in your home, you can use the following options to measure its pH level.

1. Home Test Kits

If you don’t want to spring for an electronic pH meter, you can buy home models that are shaped like pens. Other models are simple pieces of paper that change colors based on the water it’s exposed to. You can find these litmus test papers pretty much anywhere they sell fish and aquariums.

Take the strip and lay it flat, then take an eyedropper and place some drops on it. Wait for it to turn color and you’ll be able to see what pH you’re working with. Other litmus papers need to be left in water for a longer time, in which case you can place it in a shallow glass and wait to see the results.

Pen models are similar to the litmus papers in that they need to be left in a sample of the water for an extended period. However, most pen models are electric and reusable, which makes them a smarter investment if you want to continue testing pH levels regularly. These digital readouts also offer a more precise reading than litmus papers do. You’ll see exactly the number down to the decimal place, depending on the model. 

2. Electronic pH Meters

Professional monitors such as the U.S. Geological Service use more sophisticated meters to get a closer look at the acid content of water. Portable models are available to take to water sources like lakes and rivers, while larger machines are used to analyze water pH levels from inside a lab. 

These professional-grade meters are overkill for average people. The only reason scientists and researchers need them is to measure pH across huge areas. They capture precipitation and take other samples, frequently testing tens of thousands of water samples in a given year. 

How to Fix Water pH

If you do test your water and find that it’s too acidic or has a low pH, you can do a few things. If you rely primarily on well water, you can treat it with soda ash to increase acidity. If your tap water is too acidic and shows signs of corrosion, you need to have a professional check out your water pipes and possibly replace them. 

However, if you don’t see signs of corrosion and your pH level is off, a water filtration system is another way you can get your water acidity where you want it. Aim for the 6.5 – 8.5 pH level recommended by the EPA and change your water’s flavor with additives or a simple slice of lemon.

Conclusion:

Perhaps your drinking water has taken on a funny flavor or corrosion is present around your water source. Maybe you’ve heard people celebrating the virtues of alkaline water and you want to try it out. Whatever the reason for doing it, testing the pH level of your water is a simple task. 

Drinking water should be between 7 and 8 on the pH scale. You can go 0.5 degrees in either direction, but the most important thing for your hydration is to make sure the water tastes refreshing and quenches your thirst. A cold glass of well-filtered water with neutral acidity will make you feel more hydrated and allow your body to keep maintaining its own pH level the way it’s built to do.

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Joshua Perkins

Joshua spent ten years as a water systems technician in California before settling down with his wife and two young children in Nashville in 2018. Through all of his experience, he learned the benefits and shortfalls of so many different types of water filtration systems, from pitchers to whole-house installations. He started Water Filter Authority in 2019 to empower other families to make the right decision for their long-term health and wellness.