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Acid Water - Low pH

Drinking water has a normal pH range between 6 and 8.5, meaning that it typically has a level that's just below of just above neutral. There are a number of factors that can lower the pH of water, however, increasing water acidity. Acid water can cause metal pipes to corrode and leave blue-green stains on your sinks, faucets, and other plumbing fixtures. Learn more about acid water and how to address this problem.

What Is Acid Water?

Acid water is water with a low pH, meaning that it's more likely to corrode metal pipes and leach metals out of exposed surfaces.

Symptoms of Acid Water

If your water has a low pH, meaning that you have high water acidity, you may see blue-green stains on your plumbing fixtures, faucets, and drains, as well as on bathtubs and sinks. Acid in water can even cause pinhole leaks in copper plumbing. Learn more about how to treat acid water.

Water Acidity Causes

Acid water can be naturally occurring, or caused by a high level of dissolved oxygen. Other causes include certain poor plumbing practices (often related to copper piping) and incorrect electrical grounding, as well as sand or sediment in the water and high flow rates.

Are There Any Health Concerns?

The biggest health problem with acid water is related to copper pipes. Acid in water can dissolve some of the copper from the pipes, where it can be consumed in drinking water. While we all need a small amount of copper in our diets, long-term exposure to high amounts of copper in could cause serious health problems, including liver or kidney damage. Even short-term exposure can cause stomach problems, like nausea and vomiting.

Action Level

You should address acid water issues if your water has a pH lower than 6.5.

Learn More about Water Acidity

ph scaleWhat Is pH?

The pH of a solution is a measure of the activity of hydrogen ions (H+) in that solution. In practical terms, it's a measurement of how acid or basic a solution is. The pH scale ranges from 0 to 14, with lower numbers being more acidic.

  • 0 – 6.5 is Acidic
  • 7 is Neutral
  • 7.5 – 14 is Basic

In general, water with a pH that is lower than 7 is considered acid water, with lower numbers being increasingly acidic. Water with a pH that's greater than 7 is considered basic, with higher numbers being increasingly alkaline. The normal range for pH in surface water systems is 6.5 to 8.5 and for groundwater systems 6 to 8.5. Alkalinity is a measure of the capacity of the water to resists a change in pH that would tend to make the water more acidic. The measurement of alkalinity and pH are both needed to determine the corrosiveness of the water.

The pH of pure water or H20 is 7, but when exposed to the carbon dioxide in the atmosphere this results in a pH of approximately 5.2.

The Problem with Acid Water

Water that has a pH less than 6.5 could be acidic and corrosive. Acid water has the potential to leach metal ions, including iron, manganese, copper, lead, and zinc, from aquifers, plumbing fixtures, and piping. Because of its corrosive nature, this water could contain elevated levels of toxic metals, damage metal pipes. Many people also find that low pH water has a sour or metallic taste (because of the dissolved metals). It can also discolor laundry as well as plumbing fixtures.

How To Treat Acidic Water

Acidic water is typically treated with a pH water filter that includes a water neutralizer. There are two ways of neutralizing water acidity:

    1. Calcite Filters - Calcite the most common material used as a water neutralizer. It's a natural mineral, also known as calcium carbonate; in some cases, magnesium oxide (sometimes called corsex) is also used. When water flows through the calcite in the water filter, the mineral is dissolved into the water and make it less acidic. This type of filter works best on water that has a pH of 5.5 or higher. This type of pH water filter is simple to use, but the pH level may vary with the amount of time the water is in contact with the calcite. Calcite also makes the water harder, so you may need a water softener as part of your treatment system.


  1. Proportional Injection Systems - The second method for treating acid water works better on very low pH water but is also quite costly. A proportional injection system uses a chemical feed pump to inject a precise amount of water neutralizer solution into the water. This type of system typically uses a form of soda ash (a form of calcium carbonate). A proportional neutralization system assures that the pH is uniform regardless of flow rate and does not add any hardness back to the water.

If you think that you have acid water, please call our Certified Water Specialists at 1-800-608-8792.



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Our price is lower than the manufacturer's "minimum advertised price." As a result, we cannot show you the price in catalog or the product page.

You have no obligation to purchase the product once you know the price. You can simply remove the item from your cart.