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pH stands for “potential of hydrogen”.   This refers to the amount of hydrogen found in your drinking water.  pH is one of the most common water quality tests performed.  pH is the measurement of the acidic or basic level your drinking water.  The pH is measured on a scale from 0 - 14, with 7 being neutral.  A pH of less than 7 indicates acidity, whereas a pH of greater than 7 indicates a base. The normal pH range for surface water is 6.5-8.5 and the normal pH range for groundwater is 6-8.5.

What causes changes in the pH?

  1. The pH of a body of water can be affected by several factors, such as:
  2. The composition of the bedrock and soil composition that surface water and groundwater moves through.
  3. The decomposition of plant growth and organic material within a body of water (such as ponds, cisterns, springs).
  4. The dumping of chemicals into water by individuals, communities, and industries.
  5. Precipitation that falls in the watershed.
  6. Drainage from coal mine.
    • Iron sulfide, a mineral found in and around coal seams, combines with water to form sulfuric acid. This acid, ferrous oxide, and huge quantities of silt are the major pollutants from coal mining.

What are the Drinking Water Standards?

pH is classified as a secondary drinking water contaminant whose impact is considered aesthetic.  pH is not regulated; however, the USEPA has set the secondary MCL (maximum contaminant level) for pH at a range of 6.5 and 8.5.  This is a good guide for individual well owners to maintain.

pH is one of the standards used in determining the corrosiveness or staining potential of water (low pH) and the scaling or sedimentation potential of the water (high pH).  Both have an economic impact on a private water systems owner.

  • Other Standards related to corrosion and staining: Chloride, Copper, Corrosivity, Iron, Manganese, Total Dissolved Solids, Zinc.
  • Other Standards related to scale and sediments: Iron, Total Dissolved Solids, Aluminum.

What are the Health Effects?

Aesthetic problems such as an alkali (bitter) taste or scale build-up in the plumbing are created when pH levels are above 8.5; while, pH levels below 6.5 may cause aesthetic problems such as a metallic or sour taste, laundry staining or blue-green stains in sinks and drains.  Water with a low pH level can cause leaching of metals from pipes and fixtures such as copper, lead, and zinc.

If the pH of your water is too low or too high, it could damage your pipes, cause heavy metals like lead to leak out of the pipes into the water, and eventually make you sick.  Exposure to extreme pH values results in irritation to the eyes, skin, and mucous membranes.

What are the Treatment Options?

The treatment options, listed below, are not enforceable by the Local Health District or the Ohio Department of Health. These are recommended options for private water systems owner. 

Each of the treatment options are explained in detail on the following webpage link ( through the Cooperative Extension System and the Ohio State University Extension. 

  • Neutralizing Filters
  • Soda ash/sodium hydroxide injection
  • Acid injection

Contact a Registered Private Water Systems Contractor for more information about treating for excessive pH levels.

References and Additional Resources:

 Page reviewed 10/21/2014