Mercury Standards for Your Drinking Water

For many of us mercury is an element that exists only in science fiction and inside thermometers. In fact, mercury is created by natural or synthetic processes that can lead to mercury being leaked into water sources. So, should you be concerned about mercury in your drinking water?


The pure elemental form of mercury can be released during agricultural and industrial processes. It is then dispersed through the sewage systems into water sources. Unfortunately, high concentrations of the elemental form of mercury vapor can cause damage to the nervous system. The mercury most commonly traced in drinking water is inorganic mercury. This substance is often used in batteries and chemical industrial products. Although inorganic mercury has been shown to cause kitchen damage, generally this form of mercury in water is considered safe for human consumption in small quantities.

The main issues arise when bacterial organisms in the surface water convert any inorganic mercury into organic mercury. This type of mercury can pose a significant risk to health, particularly if ingested by a child. One of the most common forms of organic mercury; methyl mercury is often found in some fish. This can cause problems for water treatment plants depending on the treatment and cleaning methods used.

Drinking Water Standards:

The Safe Drinking Water Act was established by the EPA in 1974. It was designed to set regulations and guidelines on the amounts of contaminants permitted in drinking water for human consumption. While we know about the potential dangers posed now, mercury was not regulated or monitored at a national level until years later in 1992.

Once extensive testing was performed on the health risks of mercury, the EPA set the acceptable level at a very low level. In trace amounts, mercury can be dangerous and harmful. After the proper testing, the Maximum Contaminant Level was set by the EPA at 2 parts per billion and this remains the same today.

Protection From Mercury Contamination: 

The technology used to monitor the public drinking water supplies in America allows suppliers to detect mercury from water and remove it at the water treatment facility. Unfortunately, as we saw in Flint, Michigan, water treatment effectiveness in any area or region is only as good as the infrastructure and the agencies responsible for the treatment processes.

The EPA requirements state that local agencies must monitor mercury levels in public drinking water supplies regularly to comply with the Safe Drinking Water Act regulations. Once high mercury levels have been detected, the testing frequency increases to three month intervals, but these measures can take time to implement, which means that some damage may occur in the intervening period.

To ensure that your family is protected, you may wish to consider a domestic water treatment solution. Reverse osmosis is one of the only methods approved for effectively removing mercury from drinking water. If you have concerns about the possibility of mercury in your water, you should speak to a water treatment professional. A fully WQA certified professional with specific experience in mercury will ensure that you can benefit from an effective filtration system that exceeds the industry standards.

By Mark Williams (NicMar President Mark Williams holds degrees in Applied Science and Industrial Thermodynamics, along with Agricultural Mechanization and Systems Engineering from Ohio State University.  He also holds the highest possible industry ranking, being WQA (Water Quality Association) LEVEL 6 Certified.)

Print Friendly
Nicmar Water
999 Baltimore Road York SpringsPA17372 USA 
 • 800-542-8649

Water Solution Center

Educational Center