Acidity in well water usually occurs naturally a result of geological conditions but may be caused or worsened by acid rain or chemicals. Acidity, gauged on a scale known as the pH scale, is indicated by a pH of less than seven; the lower the pH, the more powerful the acid. The type of treatment used for acidic well water depends on the pH of the water and whether or not iron is also present in the well water.
Problems with Acidic Well Water
Acidic well water can be problematic for a number of reasons. Although the United States Environmental Protection Agency does not regulate private wells or require testing, homeowners are advised to have water tests conducted. Well water with an extremely low or high pH is corrosive and will leach metals from plumbing. A low pH can increase the presence of other drinking water contaminants. The acid reacts with copper and brass plumbing and fixtures to leave unsightly red stains or with galvanized plumbing to leave blue stains. Water can also have an unpleasant, metallic taste.
Tank-type Neutralizing Filters
Tank-type neutralizing filters treat water with a pH as low as six. These filters, which are installed after the water pressure tank, make water harder. Tank-type neutralizing filters send water through a magnesium oxide substance or granular calcite, which consists of marble, calcium carbonate or lime.
Water with a pH Between Four and Six
Water with a pH below six should be treated with a chemical-feed pump. Chemical feed pumps inject the well with soda ash, also known as sodium carbonate, or caustic soda, which is also known as sodium hydroxide. This process raises the sodium level in the water, which may have a negative health effect on vulnerable persons; potassium can be used as a more expensive alternative to sodium. Treat water that has a pH between four and six by adding 1 lb. of soda ash per gallon of water into the well until the faucet farthest from the well has a pH near seven.
Water with a pH Below Four
Treat well water with a pH below four with caustic soda in a chemical-feed pump. This material is extremely dangerous and should be handled only with safety goggles and gloves. Slowly add 1 lb. of caustic soda per gallon of water into the well until the water coming from the farthest faucet from the well has a pH near seven.
If well water must also be treated to remove iron, the chemical-feed pump system must be used. Several systems, filters or other treatments are avalable for treating iron-contaminated water.
- Montana State Universtiy Extension; Q & A - Water Quality Testing for Private Well Owners; Krista E. Pearson and Jim Bauder; October 2003
- North Carolina Cooperative Extension Service; Home Drinking Water Treatment Systems; Glenda M. Herman and Gregory D. Jennings; March 1996
- University of Massachusetts Extension; pH -- Acidity of Private Drinking Water Wells; June 1, 2007
- Photo Credit water well image by Stanisa Martinovic from Fotolia.com