Cadmium in Drinking Water: What You Need to Know in 2022

Cadmium is a white or silver-ish metal that has several potential health effects if consumed in drinking water.

In this glossary, we’ve shared a definition of cadmium, discussed its potential health effects and how it gets into drinking water, and offered tips on how to protect your family from exposure to this metal.

❔ What is Cadmium?

💡 Cadmium is a soft, silver or white heavy metal found in the earth’s crust. This metal is extracted as a byproduct in the mining of other metals, like lead, copper, and zinc ores. Cadmium is also commonly found with sulfur (as cadmium sulphate), chlorine (as cadmium chloride), and oxygen (as cadmium oxide).

Cadmium has wide-ranging industrial uses, including in the production of metal coatings and platings, battery technology, stabilizers in plastics, pigments, and photovoltaic cells. Cadmium is known to affect water quality, but doesn’t change the taste, smell, or appearance of water.

In Water AsCd2+
SourcesMetal leaching through corrosion of galvanized pipes
Runoff from paints and batteries
Discharge from metal refineries
Runoff from agricultural sites
Maximum
Contaminant Levels (MCLs)
US EPA: 0.005 mg/L; 0.005 mg/L (MCLG)
WHO Guideline: 0.003 mg/L
EWG: 0.00004 mg/L
Potential Health RisksRisk of kidney disease & renal damage
Cancer, including lung cancer
Nervous system and circulatory system damage
TreatmentsReverse Osmosis
Distillation

🩺 What are the Potential Health Effects of Cadmium?

In the short term, cadmium may have the following adverse health effects:

  • Chest pain
  • Coughing
  • Vomiting
  • Diarrhea

According to a factsheet produced by the Centers for Disease Control (CDC), some of the potential long-term effects of drinking elevated cadmium levels are:

  • Kidney disease & renal damage
  • Lung damage
  • Liver damage
  • Fragile bones
  • Convulsions
  • Cancer, including lung cancer
  • Blood damage
  • Nervous system damage
  • Circulatory system damage

The exact human health risks associated with cadmium consumption depend on how much this toxic metal enters the body, the length of exposure time, and how the person’s body reacts. Some people may have more serious reactions to cadmium exposure than other people.

Dialysis patient

🚰 How Does Cadmium Get Into Drinking Water?

One of the most common ways that cadmium gets into drinking water is through metal leaching.

The materials used in pipes that distribute water to your home and around your home may contribute to your cadmium consumption. It’s common for steel pipes to be galvanized – dipped in a protective coating, often containing cadmium, to prevent rust and corrosion. When water travels through these pipes, trace metals – including cadmium compounds – are released into the water.

Areas with soft water are more likely to have high dissolved cadmium in water. Why? Because water with a low pH is more acidic, meaning, two things:

  • The water is more corrosive to metal piping
  • The water is more open to picking up metal compounds

Industrial pollution, such as runoff from paints and batteries and discharge from metal refineries, can cause cadmium to leach into ground and surface waters, eventually ending up in drinking water.

Cadmium dust in the air can also settle in surface soils and water sources, causing local cadmium contamination.

Typically, regions with nearby hazardous waste sites or industrial areas are likely to have higher-than-normal cadmium concentrations in the local soil and surface water.

Finally, cadmium may also leach into surface and groundwater sources through runoff from agricultural sites.

Some phosphate fertilizers contain cadmium. When these fertilizers are washed into rivers and seep underground due to rainfall, cadmium leaches into soils, rocks, and drinking water sources.

Corroded pipes

📉 Do Water Treatment Facilities Monitor Levels of Cadmium in Drinking Water?

Yes, cadmium is monitored by water treatment facilities. According to Environmental Protection Agency (EPA) guidelines, public water systems must remove cadmium to trace levels (measured in mg/L, or milligrams per liter) that aren’t considered harmful to human health.

The following guidelines are in place for cadmium in drinking water systems:

  • EPA Maximum Contaminant Level (MCL): 0.005 mg/L
  • EPA Maximum Contaminant Level Goal (MCLG): 0.005 mg/L
  • World Health Organization (WHO) guideline: 0.003 mg/L

Public water utilities are legally required to test and treat public water to reduce EPA-flagged contaminants, including cadmium, to harmless trace levels. However, many water utilities don’t treat their water thoroughly enough to reduce cadmium to the EPA’s Maximum Contaminant Level.

🔎 How Can I Tell if Cadmium is in My Drinking Water?

Cadmium doesn’t have a taste or odor, which makes it one of the more dangerous heavy metals, because it’s not obvious in water – even at elevated levels.

The only way to know whether or not your water contains cadmium is to get your water tested.

We recommend using an accredited laboratory to get a reading of your water’s cadmium concentration. A lab report can tell you exactly how much cadmium your water contains, and the potential health risks associated with this amount of the metal.

Depending on how much cadmium is found in your water sample, you can decide on a suitable method to improve your water quality and reduce this metal in your water supply.

tap score water testing

📌 Note: If your water contains cadmium, there’s a high likelihood that it contains other metals and impurities that may impact the treatment processes you use. It’s wise to test your water for a selection of heavy metals, including copper, zinc, iron, and lead, alongside cadmium.

👩🏽‍⚕️ How Can I Protect My Family from Cadmium in Drinking Water?

Cadmium often enters your water supply from your source water or from metal plating in your pipes, so it’s usually impossible to remove this contaminant at the source. The best way to protect your family from cadmium is to install a water treatment system in your home.

Below, we’ve shared some of the top methods to avoid drinking cadmium in water.

  • Install a reverse osmosis system. One of the most thorough water treatment technologies for cadmium removal is a reverse osmosis filtration system. Reverse osmosis involves multiple filtration stages (including an RO membrane) and removes up to 99.99% TDS, including 95%-98% cadmium ions. Most RO systems are installed as countertop or under-sink applications. Read our reviews of the best RO systems in this guide.
  • Use a water distiller. Water distillers are countertop units that purify water by boiling it until it evaporates, then sending it down a cooling corridor to condense into a separate container. Contaminants that can’t evaporate at the same temperature as water, including cadmium, are left behind in the boiling chamber. Although distillation is highly effective at reducing cadmium, it’s a lengthy process, taking up to five hours to distil a single batch of water. Check out top distillers here.
  • Replace your piping. If your drinking water materials contain cadmium, the best way to greatly reduce your long-term exposure to this heavy metal is to replace all the piping in your plumbing system. This is an expensive solution, however, and you may find it more cost-effective to install a water treatment system instead.
Reverse osmosis system and distiller

⚠️ How Else Can I Be Exposed to Cadmium?

Aside from dissolved cadmium in drinking water, this metal is also present in a number of consumer products. Other ways that you could be exposed to cadmium are:

  • By contact with batteries, metal coatings, or jewellery containing cadmium
  • By eating foods that contain cadmium, like leafy vegetables, nuts, shellfish, and kidney meats.
  • By smoking. Most cigarettes contain cadmium, and up to 60% of this metal passes from cigarette smoke into the bloodstream.
  • By working in a high-risk occupation that increases your likelihood of cadmium exposure, such as welding, soldering, and the manufacturing of batteries, textiles, and plastics

📝 Where Can I Get More Information?

You can find more information about cadmium and its health effects in the links below.