Did you know that public water systems in Maine withdraw over 30 billion gallons each year to supply more than 66 percent of Maine’s population with safe drinking water? Over 20 billion gallons come from Maine’s lakes, rivers and streams. The other 10 billion gallons come from groundwater wells.

Regardless of source, each system is required to meet the same strict water quality requirements. How your water is treated generally depends on where it comes from. Surface waters are more likely to be influenced by both natural and manmade contamination; therefore they usually require the most treatment.

Drinking water from lakes, rivers and streams typically requires treatment in the form of filtration and disinfection. Filtration removes particle and prepares the water for disinfection. Disinfection is used to destroy or inactivate disease-causing bacteria and viruses.

Which technique used depends greatly on the source of the water and the size of the distribution system. Chlorine, chloramines, ozone, and/or ultraviolet light are used as disinfectants in many Maine surface-water systems. Sometimes multiple disinfection methods are needed to meet required water-quality standards. In Maine, there are 10 public water systems that are not required to filter before disinfection. These water systems have been granted a filtration waiver because their source is clean and well protected.

Treatment of groundwater is different than that of surface water. Elevated levels of iron, manganese and hardness are common in Maine groundwater and can cause significant aesthetic issues, such as bad taste and unusual color. Also, groundwater may be exposed to contaminants underground such as arsenic, uranium and radon. A common method used to remove such contaminants is ion exchange. The process removes certain minerals or contaminants from the water and returns other minerals not of concern in their place.

Chemicals may be added to further enhance the water to meet a specific need. Examples include fluoridation which aids in preventing tooth decay. Some systems treat to control corrosion of lead and copper in piping and faucet fixtures found in the homeowners’ plumbing.

Public water systems in Maine use these techniques and more to ensure that the water delivered to your home or business meets or exceeds all state and federal drinking-water standards. For more information about the treatment techniques used by your water system, give your water utility provider a call.