Problem – Acid Water, Low pH


Blue-green stains on plumbing fixtures, showers, tubs, faucets and drains, and possibly pinhole leaks in copper plumbing.


Naturally low pH water, high dissolved oxygen, poor plumbing practices (excessive flux, improper de-burring of copper pipes), improper electrical grounding, excessive sand or sediment and/or high velocity flow rates. In a high percentage of the cases, the source of the corrosion may not be determined.

Health Concerns:

Though a small amount of copper is required by the human body as an essential nutrient, long-term exposure to elevated levels of copper in drinking water may cause serious health problems. Short periods of exposure to high levels of copper can cause gastrointestinal problems, including nausea and vomiting and longer intervals may cause liver or kidney damage.

Action Level:

Over 1.0 mg/l (milligram per liter).

More Information:

pH is that it is a measure of the activity of the hydrogen ion H+. The pH scale ranges from 0 to 14.
• 0 is Acidic
• 7 is Neutral
• 14 is Basic
WaterProblem_Acid2_MedResIn general, water with a pH of less than 7 is considered acidic and with a pH greater than 7 is considered basic. 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 corrosivity 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.

In general, water with a low pH less than 6.5 could be acidic and corrosive. Therefore, the water could leach metal ions such as: iron, manganese, copper, lead, and zinc from the aquifer, plumbing fixtures, and piping. Also, a water with a low pH could contain elevated levels of toxic metals, cause premature damage to metal piping, and have associated aesthetic problems such as a metallic or sour taste, staining of laundry, and the characteristic blue-green staining of sinks and drains . The primary way to treat the problem of low pH water is with the use of a neutralizer.

There are two ways of providing neutralization of acidic waters:

1. Calcite Filter – This is the most common way to neutralize pH. The water flows through a tank containing a mixture of a nautural mineral called calcium carbonate (calcite) or magnesium oxide (sometimes called corsex), which is absorbed by the water and raises the pH. This method works best on water which has a pH of 5.5 or higher. The main advantage of this is that it is simple to use! The main disadvantage is that when the water sits in contact with the Calcite, like overnight, the first water which comes out may have a higher pH, but under extremely high flow rates, the pH level may be raised only slightly. A Calcite filter also add hardness to the water, so in many cases you would want to follow it with a water softener.

2.Proportional Injection System – The second method, which is superior on low pH water, but most costly, involves using a chemical feed pump to inject a precise amount of soda solution into the water to prevent the water from reacting with the house plumbing or contributing to electrolytic corrosion – a typical neutralizing chemical is soda ash. The Proportional Neutralization System assures that the pH is uniform regardless of flow rate and does not add any hardness back to the water.