What are the effects of mercury in tap water?

February 08, 2024 3 min read

What are the effects of mercury in tap water?

Tap water tends to get a bad reputation, but there is still much discontent over whether or not that reputation is earned. In reality, the quality of your tap water varies based on geographic location, the age and material of your pipes, and many other factors. With this in mind, let’s explore one of the most dangerous contaminants that could enter your water: mercury. 

What is mercury?

Mercury is a naturally-occurring element known as a heavy metal. Heavy metals are high in toxicity and found in the earth’s crust. In the case of mercury, it is found in rock, soil, and water (1). While highly dangerous to consume, mercury is necessary in the production of many household items, including electronics, batteries, and fluorescent lightbulbs. Additionally, mercury is often used to power laboratory and industrial instruments (2). 

How does mercury enter your water supply?

Mercury is found naturally throughout the environment. It originates in rocks and soil, and wind and rain can carry it into surface water supplies, like rivers or lakes. 

However, mercury contamination is not always due to natural causes. In the past, many pesticides were mercury-based, and many farms still hold the remnants of mercury in their fields. Runoff from agricultural lands can also make its way into groundwater supplies, which then carries mercury into nearby households through tap water. Additionally, industrial and hazardous waste sites pose a risk of mercury contamination (3). Improper disposal of products containing mercury, like outdoor paint or electronic waste, can seep into water supplies and expose public and private groundwater sources to mercury. 

Health effects of mercury

Mercury is highly toxic if consumed, and it comes with a slew of negative health effects. In the short term, drinking mercury puts you at risk of mercury poisoning, which is associated with lack of coordination, muscle weakness, nerve damage, and hearing difficulties. Long-term effects of mercury consumption include impeding cell functions like growth and damage-repair, as well as damage to the nervous system and kidneys (1). According to a study conducted at the University of Georgia, “Young children and developing fetuses are especially susceptible to the harmful effects of mercury” (4). 

Regulations on mercury in tap water

To protect against the harmful effects of mercury in public water sources, the Environmental Protection Agency took steps to regulate the contaminant. In 1991, the Safe Drinking Water Act set the maximum contaminant level at 0.002 milligrams per liter (5). This set enforceable regulations that public water systems need to follow before sending out their water into homes. Every three months, public water sources are tested for mercury contamination. If a source is regularly exceeding the legal limits, the source must remove the contaminant from the water (6). 

Note that private water sources, like well water, are not regulated by the EPA. These supplies should be tested by the owner of the water source and regularly maintained to ensure the water is free from heavy metals like mercury (4). 

How to remove mercury from your tap water

As previously mentioned, public water supplies are regularly monitored and will remove mercury from your tap water if it regularly tests above the legal limits. Methods approved for doing so include filtration, granular activated carbon, lime softening, and reverse osmosis (6). 

However, these methods are only implemented after multiple offenses of the water being tested. This means that your water can be contaminated with levels of mercury for six months minimum before any action is taken. To avoid unknowingly drinking water contaminated with mercury, consider investing in a Seychelle radiological water filter. Seychelle RAD filters are independently lab-tested to remove up to 99.99% of heavy metals–including mercury–from your water. 

The Wrap-Up

Mercury is a highly toxic heavy metal that occurs naturally in the environment. Due to both natural causes and human intervention, mercury can seep into groundwater supplies and enter your tap water. Despite public regulations, it is recommended to be on the safe side when it comes to your water to protect yourself and your family from mercury poisoning. For the peace of mind knowing that your water is mercury-free and ready to drink, choose Seychelle.

Frequently Asked Questions

What is the effect of mercury in water on human health?

Mercury is extremely dangerous if consumed. Mercury poisoning can cause muscle weakness, decrease coordination, and damage nerve, cell, and kidney function. 

Is tap water high in mercury?

Mercury is regulated to not exceed 0.002mg/L in public water sources. These sources are tested every three months, but the amount of mercury in a given water source varies based on location. 

What removes mercury from water?

The EPA approves of filtration, granular activated carbon, lime softening, and reverse osmosis as ways to remove mercury from water. 


  1. NC Department of Health and Human Services,https://epi.dph.ncdhhs.gov/oee/docs/Mercury_WellWaterFactSt.pdf 
  2. World Health Organization,https://www.who.int/docs/default-source/wash-documents/wash-chemicals/mercury-background-document.pdf?sfvrsn=9b117325_4 
  3. New Jersey Division of Environmental and Occupational Health,https://www.hopewelltwp.org/DocumentCenter/View/114/Facts---Mercury-in-Drinking-Water-PDF
  4. University of Georgia,https://secure.caes.uga.edu/extension/publications/files/pdf/C%20858-13_2.PDF 
  5. Environmental Protection Agency,https://www.epa.gov/mercury/what-epa-doing-reduce-mercury-pollution-and-exposures-mercury#drinking
  6. University of Wisconsin-Eau Claire,https://people.uwec.edu/piercech/hg/mercury_water/drinkingwater.htm