Selenium in Drinking Water: Health Risks, Sources, and How to Remove It
Selenium is an inorganic contaminant that can be found in drinking water supplies. The U.S. Environmental Protection Agency (EPA) regulates this element to protect public health. The Maximum Contaminant Level (MCL) set by the EPA for selenium in public drinking water is 50 μg/L.
Health Effects
Exposure to high levels of selenium in drinking water can cause several adverse health impacts. Consuming water with selenium above the regulatory limit may lead to hair and fingernail loss, as well as feelings of numbness. Additionally, prolonged exposure is associated with circulatory problems.
How Selenium Gets Into Tap Water
Selenium enters drinking water supplies through both natural and industrial pathways. It can leach into water sources from natural geologic deposits in the earth. Additionally, human activities such as mining and petroleum refining can release selenium into the environment.
How to Remove Selenium From Your Water
Several standard treatment technologies can be used to remove selenium from drinking water. These treatment methods include activated alumina, reverse osmosis, and ion exchange systems. Filtration systems utilizing these techniques are commonly used to reduce selenium levels effectively.
Should You Test Your Water?
If you are concerned about selenium in your water, you can check your local utility's annual consumer confidence report or use the WaterQ search tool. Testing through a certified laboratory is recommended for those relying on private wells near mining or industrial areas. You can also look up your local water system on WaterQ or check the Selenium data page for reported levels in your area.
Frequently Asked Questions
Is Selenium dangerous in drinking water?
Yes, elevated levels of selenium in drinking water can cause adverse health effects. Long-term exposure above the safe limit can result in hair and fingernail loss, numbness, and circulatory problems. However, maintaining levels below the EPA limit of 50 μg/L prevents these issues.
How does Selenium get into tap water?
Selenium gets into tap water by eroding from natural deposits in the ground. It can also enter water sources through industrial processes like mining and petroleum refining.
How can I remove Selenium from my water?
Selenium can be removed using water treatment methods such as activated alumina, reverse osmosis, or ion exchange. These technologies are effective at reducing selenium levels to meet safety standards.
Source: EPA National Primary Drinking Water Regulations and WaterQ National Database. For more contaminants, visit our contaminant library.
What actually removes heavy metals (mercury, cadmium, barium and others)
Reverse osmosis handles the whole group reliably, which makes it the simple answer when several metals show up at once. Some NSF/ANSI 53 carbon filters carry claims for specific metals such as mercury and cadmium — check the claim names on the performance data sheet rather than assuming a lead-rated filter covers the rest. A softener is a partial exception: ion exchange does capture barium reasonably well, though it does nothing for most of the others.
Works
- Reverse osmosis (NSF 58)The broadest removal available at home: arsenic, nitrate, fluoride, PFAS, TDS.
- Carbon certified for lead (NSF 53)The cheapest thing that genuinely removes lead, cysts and many VOCs.
Will not fix this
- Basic activated carbon (NSF 42)
- UV disinfection (NSF 55)
- Boiling Makes it worse — evaporation concentrates what's left behind.
Test before you buy.Heavy metals (mercury, cadmium, barium and others) can't be seen, tasted or smelled, and the right hardware depends on the concentration you actually have. A certified lab test costs a fraction of the wrong filtration system. Start with your local water quality report, and get a mail-in lab test if you're on a private well.
Options that carry the right certification
Ordered cheapest-adequate first. Prices are indicative bands and move often.
| Product | Certification | Upfront | Per year | |
|---|---|---|---|---|
| APEC ROES-50 EssenceUnder-sink | Built with WQA-certified components to NSF/ANSI 58.Catch:Needs an under-sink drain connection and a spare hole for the dedicated faucet. Strips minerals — some people dislike the flat taste. | $180–240 | $50–80 | Check price |
| AquaTru Countertop Reverse OsmosisCountertop | NSF/ANSI 42, 53, 58, 401 and P473 certified.Catch:Takes counter space and you refill a tank by hand. Wastes some water as brine, like all RO. | $400–500 | $80–130 | Check price |
| Brita Elite Pitcher FilterPitcher | NSF/ANSI 42 and 53 certified, including a lead reduction claim.Catch:No fluoride, nitrate or arsenic reduction. Not PFAS-rated. | $25–40 | $50–70 | Check price |
| iSpring RCC7AK 6-Stage ROUnder-sink | WQA Gold Seal certified to NSF/ANSI 58.Catch:The alkaline remineralization stage adds minerals back, which slightly raises TDS readings — expected, not a fault. | $200–280 | $60–90 | Check price |
Certification listings change. Before buying, confirm the current listing for the exact model in the NSF certified products database — a manufacturer's marketing page is not a certification. WaterQ earns a commission on purchases made through these links at no extra cost to you; see our affiliate disclosure. This is general information, not medical or engineering advice.
For a full breakdown of certifications, running costs and the models worth considering, see our buying guide for heavy metals (mercury, cadmium, barium and others).