What is pH in drinking water?

The pH level of your drinking water reflects how acidic it is. pH stands for “potential

hydrogen,” referring to the amount of hydrogen mixed with the water. pH is measured

on a scale that runs from 0-14. Seven is neutral, indicating there is no acid or alkalinity

present. A measurement below 7 indicates acid is present and a measurement above 7

indicates alkalinity.

The normal range for pH in ground water lies between 6 and 8.5. By comparison, vinegar

measures 3 pH, beer measures between 4 and 5, while milk measures around 6.4 pH.

Water with a low pH can be acidic, soft and corrosive. This water can leach metals from

pipes and fixtures, such as copper, iron, lead, manganese and zinc. It can also cause damage

to metal pipes and aesthetic problems, such as a metallic or sour taste, laundry staining or

blue-green stains in sinks and drains.

Water that contains elevated levels of toxic metals could also show a low pH level.

Drinking water with a pH level above 8.5 could indicate that the water is hard. Hardness

does not pose a health risk, but can cause aesthetic problems, such as an alkali taste to the

water that makes coffee taste bitter; build-up of scale on pipes and fixtures than can lead

to lower water pressure; build-up of deposits on dishes, utensils and laundry basins; difficulty

in getting soap and detergent to foam; and lowered efficiency of electric water heaters.

What are the health effects of pH?

The U.S. Environmental Protection Agency (EPA) does not regulate the pH level in drinking

water. It is classified as a secondary drinking water contaminant whose impact is considered

aesthetic. However, the EPA recommends that public water systems maintain pH levels of

between 6.5 and 8.5, a good guide for individual well owners.

How do I test for pH?

Contact your local health department for a list of state-certified laboratories that can test

the pH level of your water. If it is acidic, less than 7 pH, you may have problems with leaching

of copper and lead from your plumbing. Consider testing for lead if the pH test shows

your water is highly acidic.

What is the treatment for pH in drinking water?

Treat the problem of acidic, low pH drinking water with a neutralizer. The neutralizer feeds

a solution, typically using soda ash, into the water to prevent the water from reacting with

the house plumbing or contributing to corrosion, which can leach metals into the water.

Note: neutralizing with soda ash increases the sodium content of the water, which may pose

additional health concerns for your household.

Treat hard water with a high pH with an ion-exchange system or the addition of a lime-soda

ash mixture. These processes also can increase the sodium content of the water. Contact your

water well professional or your local or state health department for guidance.

For more information about pH and other drinking water contaminants

www.epa.gov/safewater/consumer/2ndstandards.html

www.nsf.org/consumer/drinking_water/dw_well.asp?program=WaterTre

Wilkes University, Center for Environmental Quality, GeoEnvironmental Sciences and

For more information on your drinking water

The following sites provide up-to-date information on efforts to protect drinking water

supplies and steps you can take as a private well owner:

nonprofit organization dedicated to promoting the wider use of wells as

modern and affordable safe drinking water systems and to protecting

ground water resources nationwide. Well owners and others with questions

This publication was developed in part under Assistance Agreement No. X-82849101-4 awarded by the U.S. Environmental

Protection Agency. It has not been formally reviewed by EPA. The views expressed in this document are solely those of

WSC. EPA does not endorse any products or commercial services mentioned in this publication.