What happens if the pH of water is low?

Studies show that water with a low pH can cause significant issues, ranging from corroding your home's plumbing to impacting aquatic ecosystems. Understanding what happens if the pH of water is low is crucial for protecting your health and property.

Quick Summary

Low water pH, or acidic water, can cause extensive damage to plumbing and appliances through corrosion, potentially leaching harmful metals. It can also harm aquatic life and cause aesthetic issues like fixture staining.

Key Points

• Corrodes Plumbing: Low-pH (acidic) water is corrosive, eating away at metal pipes like copper, galvanized steel, and iron, leading to leaks and failures.

• Leaches Heavy Metals: As it corrodes pipes, acidic water leaches harmful metals like lead and copper into the drinking water, posing serious health risks.

• Causes Aesthetic Issues: Signs of acidic water include blue-green stains on fixtures from copper corrosion, rust-colored stains from iron, and a metallic or sour taste.

• Damages Appliances: Water-using appliances like water heaters suffer reduced efficiency and premature failure due to internal component corrosion from low-pH water.

• Harms Aquatic Ecosystems: Runoff of acidic water into rivers and lakes can disrupt aquatic life by altering pH, releasing toxic metals from sediment, and harming sensitive organisms.

• Requires Treatment: Solutions include neutralizing filters using calcite or magnesium oxide, or chemical injection systems with soda ash for severe cases.

Understanding the pH Scale and Acidic Water

The pH scale is a logarithmic measurement that indicates the acidity or alkalinity of a substance, ranging from 0 to 14. A pH of 7 is neutral, with lower values indicating increasing acidity and higher values indicating alkalinity. In general, water with a pH below 6.5 is considered acidic and can be corrosive. Several factors can cause water's pH to drop, including natural geological conditions, decaying organic matter, acid rain from atmospheric pollution, and industrial runoff. When water becomes acidic, its corrosive nature sets off a chain of potentially serious problems for your home's infrastructure and the health of those who use it.

The Damaging Impact on Your Home's Plumbing and Appliances

One of the most immediate and costly consequences of low-pH water is its corrosive effect on metal plumbing and water-using appliances. Acidic water actively seeks to balance itself by dissolving minerals and metals from any material it contacts, a process that can lead to significant infrastructure damage over time.

Plumbing Damage and Visible Signs

• Copper Pipes: Acidic water can eat away at copper pipes, leading to pinhole leaks and significant water damage. A telltale sign of this corrosion is the appearance of blue-green stains on sinks, tubs, and faucets where the water has evaporated.
• Galvanized Steel and Iron Pipes: For homes with galvanized steel or cast-iron pipes, low-pH water accelerates rust formation. This can lead to rust-colored or red-brown staining on fixtures and can also cause internal pipe blockages, reducing water pressure and eventually leading to failure.
• Leaching of Heavy Metals: As pipes corrode, the metals they are made of, such as copper, lead, and zinc, can leach into the water supply. This is particularly dangerous in older homes that may still have lead solder or piping, as ingesting lead can have severe health consequences.

Damage to Water-Using Appliances

Acidic water also shortens the lifespan of appliances that use or heat water, including water heaters, dishwashers, and washing machines. Corrosion of internal components reduces efficiency and leads to premature equipment failure, resulting in expensive repairs or replacements.

Health Risks Associated with Low-pH Water Consumption

While the pH of water itself is not the main health threat, the heavy metals it leaches from plumbing are. These metals can accumulate in the body over time, posing significant health risks.

Heavy Metal Toxicity

• Lead: Elevated levels of lead, leached from older pipes or solder, are especially harmful to children and infants, affecting neurological development.
• Copper: High concentrations of copper can cause gastrointestinal distress, including nausea and vomiting.
• Other Metals: Other heavy metals mobilized by low pH water, such as cadmium and aluminum, also increase in toxicity and can cause physiological damage.

Direct Effects on the Body

• Digestive Issues: Regular consumption of acidic water can irritate the stomach and esophagus, potentially worsening conditions like acid reflux.
• Dental Erosion: The corrosive nature of acidic water can slowly erode tooth enamel, making teeth more vulnerable to decay and cavities.
• Skin Irritation: Washing with low-pH water can strip the skin of its natural oils, leading to dryness, itching, and worsening conditions like eczema.

Environmental Consequences of Acidic Water

The effects of low-pH water extend far beyond a single home. When acidic water enters natural bodies like rivers and lakes, it disrupts the entire aquatic ecosystem.

• Harm to Aquatic Life: Most fish and invertebrates are sensitive to pH changes. Acidification can harm reproduction, growth, and survival rates. Fish mortality increases significantly in highly acidic water, and the release of toxic metals from sediment further stresses organisms.
• Impact on Plant Life: Acidic water can affect aquatic plants by altering the availability of essential nutrients, potentially leading to algae blooms that deplete dissolved oxygen and harm other organisms.
• Ocean Acidification: An increase in dissolved carbon dioxide in oceans causes a decrease in pH. This specifically impacts calcifiers, like corals and molluscs, making it harder for them to build and maintain their shells and skeletons.

Comparison of Low pH vs. High pH Water

Feature	Low pH (Acidic) Water	High pH (Alkaline) Water
Corrosive Nature	Highly corrosive to metals; dissolves and leaches metals from pipes and fixtures.	Non-corrosive, but can cause scale buildup (mineral deposits) inside pipes and appliances.
Aesthetic Issues	Blue-green stains (copper pipes), rust-colored stains (iron pipes), metallic or sour taste.	Scaling on fixtures and inside pipes, bitter or soda-like taste, slippery feel.
Health Concerns	Primary risk is heavy metal poisoning from leached metals; can irritate skin and digestive system.	Generally less harmful, but can interfere with chlorine disinfection at high levels and may cause digestive issues in sensitive individuals.
Equipment Impact	Damaging to metal components in appliances like water heaters, leading to reduced efficiency and failure.	Reduces efficiency of water heaters by insulating heating elements with scale buildup.

Testing and Treating Low-pH Water

Correcting low-pH water requires testing and often installing a treatment system. The first step is to test your water. Simple at-home kits can give an indication, but a professional lab test is recommended to determine the exact pH and presence of heavy metals. For private well owners, regular testing is crucial.

• Neutralizing Filters: These systems are the most common treatment for acidic water. Water is passed through a tank filled with an alkaline media, such as calcite (crushed limestone) or magnesium oxide, which dissolves to raise the water's pH. The media is depleted over time and needs to be periodically replenished.
• Chemical Injection: For severely acidic water (below 5.5 pH), a chemical injection system can be used to add a solution of soda ash (sodium carbonate) or caustic soda (sodium hydroxide) directly into the water supply. This provides a precise and controlled method for pH correction.
• Aeration: In cases where acidity is caused by dissolved carbon dioxide, aeration can help by stripping the gas from the water. This is often used in conjunction with other methods.

Conclusion: The Importance of Addressing Low pH Water

Ignoring low-pH water is a risk to your home's infrastructure, your family's health, and the local environment. The corrosive nature of acidic water causes gradual but significant damage to plumbing and appliances, leading to costly repairs and potential heavy metal contamination. Health issues, from digestive discomfort to dental erosion and toxicity from leached metals like lead, are serious concerns associated with long-term exposure. Fortunately, a combination of regular water testing and effective treatment systems, such as neutralizing filters or chemical injection, can mitigate these risks. Taking proactive steps to maintain a balanced water pH is essential for protecting both your property and well-being.

For more detailed information on water quality issues, consult the official USGS Water Science School.

Frequently Asked Questions

What is considered a low pH for water?

While a pH of 7 is neutral, water with a pH below 6.5 is generally considered acidic and is more likely to be corrosive.

Is it dangerous to drink water with a low pH?

Drinking low-pH water itself isn't the primary danger; the main health risk comes from the heavy metals, like lead and copper, that it leaches from your plumbing as it corrodes.

What are the common signs of acidic water in a home?

Common signs include blue-green stains on plumbing fixtures, especially with copper pipes, rust-colored stains with iron pipes, a metallic or sour taste in the water, and frequent leaks.

How can I test the pH of my water?

You can use at-home test kits for an initial reading, but for the most accurate results on both pH and heavy metal content, a professional lab analysis is recommended.

What are the treatment options for low-pH water?

Treatment options include installing a neutralizing filter that uses an alkaline media like calcite, or for more severe cases, a chemical injection system that adds soda ash or caustic soda.

Can acidic water affect my skin and teeth?

Yes, acidic water can irritate skin by stripping natural oils and can also erode tooth enamel over time, potentially leading to cavities and sensitivity.

What causes water to have a low pH?

Low pH can be caused by natural factors like runoff from surrounding rock and soil, decaying organic matter, and volcanic activity, as well as human-induced factors such as industrial pollution and acid rain.