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Acidic water refers to water with a pH of less than 7 (1).

The pH of water indicates how acidic or basic (alkaline) it is. This measure can range from 0 to 14, with a pH of 7 being neutral (2).

While the United States Environmental Protection Agency (EPA) does not regulate the pH of drinking water, it does recommend keeping public water within a pH range of 6.5 to 8 (3).

Acidic water has been claimed to have antimicrobial effects, making it potentially beneficial for skin, hair, and washing produce. However, it can also have many undesirable and potentially dangerous side effects.

This article reviews what acidic water is, its potential downsides and benefits, and how to remove it from your drinking supply.

In contrast to alkaline water, which has a pH greater than 7, acidic water has a pH of 6.5 or less (2).

There are many causes of low pH water, including natural causes like acidic rain. Soil microbes, tree roots, and some rock formations can also generate acids that cause nearby water to become acidic (2).

Oftentimes, acidic water is due to industrial pollution, with low pH water often being found near mining sites, chemical dumps, power plants, confined animal feeding operations, and landfills (2).

Summary

Acidic water has a pH of 6.5 or less and can be caused by natural phenomena, as well as industrial pollution.

It’s not recommended to drink acidic water, as it’s high acidity and concentration of heavy metals can have several negative health consequences.

May contain heavy metals

One of the main concerns with acidic water is that it often contains high amounts of heavy metals (1).

Research has found that solutions with lower pH levels are more likely to leach heavy metals from the environment. As a result, the solution — in this case, water — ends up with a higher concentration of heavy metals (1, 4).

In particular, acidic water can be high in lead, arsenic, copper, nickel, cadmium, chromium, and zinc (1, 5).

This is concerning, as exposure to heavy metals can be dangerous, potentially leading to heavy metal poisoning and toxicity, symptoms of which include the following (6, 7):

  • diarrhea
  • nausea and vomiting
  • abdominal pain
  • chills
  • weakness
  • shortness of breath
  • suppression of the immune system
  • organ damage

The severity of these side effects depends on several factors, including age, sex, individual susceptibility, and the route, dose, and frequency of exposure (6).

Children, in particular, have been shown to have more severe side effects from heavy metal exposure, including an increased risk of developmental delays, respiratory issues, behavioral disorders, certain forms of cancer, and heart disease (8, 9).

May be bad for your teeth

The pH of food and beverages plays an important role in your overall dental health.

In particular, tooth enamel — the hard, outer surface of your teeth that protects it against decay — is susceptible to damage from acidic beverages (10).

While acidic groundwater hasn’t been studied specifically, beverages with a pH of 4.5 or less have been shown to increase the risk of tooth decay. As such, regularly drinking acidic water may slowly erode your tooth enamel, causing cavities (10, 11).

May be bad for bone health

Consuming acidic water has been claimed to prevent calcium absorption and lead to bone loss over time.

Yet, research hasn’t shown that the pH of your diet significantly affects your risk of bone loss, nor has it consistently shown that drinking alkalized water has a protective effect (12).

However, exposure to certain heavy metals, including lead, cadmium, arsenic, and chromium, has been linked to negative side effects for bone health (13, 14).

Therefore, regular exposure to acidic water that’s high in these heavy metals may have negative effects on bone health over time.

Can damage the plumbing in your house

In addition to harming your body, acidic water can corrode pipes.

Due to its high acidity, water with a low pH can start to dissolve metal pipes over time, causing leaks and further increasing the presence of heavy metals in your drinking supply (15).

Signs that your pipes may be experiencing corrosion due to acidic water include blue-green stains on your faucets or in your sink, metallic-tasting water, and pinhole leaks in your plumbing (15).

Summary

Due to potential heavy metal contamination, it’s not recommended to drink acidic water, as it can lead to heavy metal poisoning or toxicity. Additionally, the acidity of the water can erode tooth enamel and metal plumbing in your house.

While it’s not recommended to drink acidic water, topical use may have some benefits.

May help treat inflammatory skin conditions

Acidic water is known to have potent antimicrobial effects. In particular, it has been shown to be effective against Staphylococcus aureus, which can cause and exacerbate symptoms of atopic dermatitis (16, 17, 18).

Atopic dermatitis is a chronic inflammatory skin condition that causes red, itchy rashes. While research is limited, the topical application of acidic water may reduce redness and itchy skin associated with atopic dermatitis (17, 18, 19).

One study in 18 women with chronic atopic dermatitis found that bathing in acidic water was just as effective at reducing the severity of atopic dermatitis symptoms as a standard treatment called wet-wrap dressing (17).

As the surface of your skin is slightly acidic, increases in pH have been found to have a dehydrating and irritating effect on the skin. Research has also shown that several inflammatory skin diseases, such as eczema, are often accompanied by a rise in pH (20, 21).

As a result, it’s thought that acidic water may help maintain a desirable skin pH, protecting against inflammatory skin conditions and keeping the skin hydrated (21).

One study in 10 healthy women found that applying an acidic water and oil emulsion after washing with tap water and soap helped maintain a desirable pH on the surface of the skin (22).

While this study suggests that acidic-water-based skincare products may help protect the skin against inflammatory skin conditions related to rises in pH, more research is needed on its long-term effectiveness.

May help maintain the optimal pH of your hair and scalp

As your hair and scalp also have more acidic pH levels, acidic water is thought to have benefits for hair health, including preventing hair loss and reducing dandruff.

One study in 184 women found that the presence of Staphylococcus epidermidis and Malassezia species on the scalp were highly associated with dandruff (23).

Given that acidic water has been shown to have potent antimicrobial effects, it may help treat dandruff. However, research has not confirmed its effectiveness.

Similarly, while studies have found that shampoos with a pH greater than 5.5 may increase friction and cause hair breakage, no research to date has shown that acidic water prevents hair breakage or loss (24).

Other proposed benefits

Due to its antimicrobial effect, some recommend cleaning fruits and vegetables with acidic water.

Acidic electrolyzed water is an acidic water made with hydrochloric acid. While research is limited, several studies have found it to be safe and effective at reducing bacteria and other foodborne pathogens in fresh produce (25, 26, 27).

However, it’s unclear whether other sources of acidic water are just as safe and effective for rinsing fruits and vegetables.

Acidic water has also been suggested to be better for the growth of plants, as well as protecting against bugs and pests.

One study in tomato plants found that spraying the seeds with acidic electrolyzed water significantly reduced the number of bacterial pathogens without affecting the growth of the tomato seeds (28).

Therefore, acidic water sprays may be an effective way to protect plants against damaging pathogens. Still, more research is needed on its long-term effects on a variety of plant species.

While many plants prefer a slightly acidic soil for growth, pH levels of 3.0 or less can impair the growth of many plants by reducing nutrient availability and water uptake (29, 30).

Overall, before using acidic water on your plants, it’s important to research the optimal pH for your particular plant species.

Summary

The topical use of acidic water may be beneficial for inflammatory skin conditions like atopic dermatitis. It may also help with dandruff, washing fresh produce, and growing plants. However, more research is needed to confirm these effects.

While authorities generally keep the pH of drinking water in a neutral range, you can easily check the pH of your water using a home testing kit.

As long as your water falls within the EPA’s recommended range of 6.5 to 8.5, you’re safe to drink the water. However, if the pH is below 6.5, it’s important to call your local water company to notify them of your findings.

Unless you have a private well, the local water company is responsible for investigating and fixing the potential cause of the acidic water. In the meantime, you can use a water filtering pitcher, such as a Brita, or install a filtering system in your sink.

If you have a private well and find that your water supply is consistently acidic, you may need to install a neutralizing filter to help protect your health, as well as the pipes in your house.

Summary

You can easily test the pH of your water supply using a home testing kit. If your water is acidic, it’s important to let your water supply company know and use a water filtering system. Neutralizing filters can also be installed if you have a private well.

While acidic water is often the result of industrial or chemical contamination, it can be caused by natural phenomena.

Due to its antimicrobial effects, the topical use of acidic water may be beneficial for inflammatory skin conditions like atomic dermatitis, hair health, and growing plants.

However, drinking acidic water is not recommended, as it may lead to heavy metal poisoning and toxicity with repeated exposure. Additionally, its high acidity may corrode your teeth and the pipes in your home.

If you’re concerned about the pH of your drinking water, be sure to buy a home testing kit and use a filtering system if needed.

Shop for water testing kits online.