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

Mold in drinking water is thankfully rare, but is known to have several concerning health effects.

This glossary will discuss the most important information about mold exposure in water, including the likely causes of mold contamination, and how to remove mold from your water supply.

❔ What is Mold?

💡 Mold is a type of fungal spore that typically spreads on damp and decaying matter.

Molds are found in all environments, both indoors and outdoors, at all times of the year. There are numerous types of mold spores today, typically found in shades of brown, black, white, orange, purple, green, yellow, pink, red, or a combination of colors. Green mold is considered the most common, and black mold is considered the most dangerous.

Mold releases tiny spores to reproduce. These spores travel to different locations by floating through the air. Mold growth is everywhere, so avoiding exposure to mold is virtually impossible. Breathing mold spores in the atmosphere is our biggest source of mold exposure.

Moldy faucets

There are several industrial and pharmaceutical uses of mold. Certain molds are used in the production of various pharmaceuticals (like antibiotics), pigments, foods and beverages, and enzymes.

In Water AsSpecies of filamentous funguslike organisms (phylum Oomycota, kingdom Chromista)
SourcesPrivate well
Water pipes
Secondary Maximum
Contaminant Level (SMCL)
No maximum levels
Potential Health RisksRisks of mycotoxicosis (mold poisoning)
Asthma attacks
Skin rash
Red or watery eyes
TreatmentsReverse Osmosis
UV Purification

🩺 What are the Potential Health Effects of Mold?

Different types of mold spores have different health effects – and some mold has no health effects whatsoever.

According to WebMD, people most sensitive to the effects of mold are children, the elderly, people with lung disease, and people with compromised immune systems.

The most common effects of mold are seen in people who have mold allergies. The symptoms of a minor mold allergy are:

  • Sneezing
  • Red or watery eyes
  • Runny nose
  • Skin rash
  • Itching
  • Scratchy throat

A serious mold allergy may cause the following reactions:

  • Shortness of breath
  • Asthma attacks
  • Tiredness
  • Coughing
  • Weight loss

Some types of mold (especially black mold) are toxigenic, meaning that they produce mycotoxins, which make you sick.

According to Medical News Today, symptoms of mycotoxicosis (mold poisoning) are:

  • Headaches
  • Body aches and pains
  • Mood changes
  • Nosebleeds
  • Memory loss

Drinking moldy water has its own set of potential health effects:

  • Nausea
  • Respiratory problems
  • Abdominal cramping
  • Diarrhea
  • Unexplained infections

The symptoms you experience from mold exposure depend on the type of mold you’re exposed to, in what way, and for how long. Over time, people can develop something called toxic mold syndrome if they’re continuously exposed to black mold. Exposure to mold is rarely deadly.

Health effects of mold

🚰 How Does Mold Get Into Drinking Water?

Mold may be found naturally in drinking water sources, but it’s usually filtered out of water during water treatment.

📌 Most commonly, mold enters water on its journey into your home. If your hot water heater, your well system, your faucets, or your water pipes have accumulated mold, some of this mold may dislodge and get into your water supply.

Moldy is especially common in homes with a private well system. If your well cap is dislodged or damaged, mold spores may be able to enter your well system. Your well water storage tank could also accumulate mold if air gets into the tank.

Mold growth in water pipes is uncommon, but not impossible. Water pipes are moist and dark, providing the ideal environment for mold. However, your pipes shouldn’t have adequate oxygen for extensive mold growth.

Another way that mold can get into water is through an old water filter. If you own a carbon or paper filter cartridge that you don’t change regularly, mold will begin to grow in the filter media. When you treat water in the filter, some of the mold will break off and contaminate the water.

Your water is more likely to contain mold if it has high oxygen levels and your pipes and plumbing are rich in organic food particles.

Some molds in water are evolved to live in fresh or brackish environments. There are more than 150 species of water-dwelling mold, most of which live on dead and decaying matter.

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

Yes, water distribution systems should monitor mold in drinking water – but there aren’t any official legal regulations for mold reduction.

Mold grows naturally in the environment, but it isn’t commonly found in high concentrations in water supplies. Most national organizations, including the World Health Organization, list fungi like mold as “nuisance organisms” that only cause odor problems and don’t need dedicated monitoring.

Plus, when public water facilities treat water to kill microbes, mold is typically reduced as well.

📌 Because of this, the EPA doesn’t currently regulate mold in the National Primary Drinking Water Regulations, and there are no Maximum Contaminant Levels or Maximum Contaminant Level Goals for this impurity.

Water suppliers are legally required to test their water for contaminants. If mold is detected in water, your supplier should take extra effort to remove it.

laboratory water testing

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

Some types of mold in water are obvious. You may notice black floating clumps of mold or furry mold spores. However, this is an extreme example of mold, and you probably won’t notice tiny particles of mold in your water.

Some of the signs that you have mold in your water are:

  • Moldy smell when you switch on your tap. Water shouldn’t have a smell. If you can smell mold or you notice a sour smell when you turn on your faucet, you may have a mold problem. The smell could also be coming from a moldy drain, so smelling mold doesn’t guarantee that the mold is present in your water.
  • Mold in your home. If you notice mold growing on your home’s walls and ceilings, that means your home is the right environment for mold to grow in. You’re more likely to have mold in your water pipes if other places in your home are moldy.
  • Gritty substance in your toilet. If the bottom and sides of your toilet are coated with a gritty, dirt-like substance, there’s a good chance you have mold-contaminated water.
  • Mold in pipes. If you see mold in an accessible pipe, your entire water line may be contaminated.

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

To protect your family from drinking moldy water, you first need to know the cause of the mold.

water testing with tap score

If your well cap is damaged or not sealed properly, repair or seal the cap to prevent mold from contaminating your well.

If you’re pretty certain that mold is coming from your water pipes, you can remove the mold with a white vinegar and baking soda solution, or with half a cup of household bleach. This solution can only be used to remove mold spores from your drain pipes. If you want to eliminate mold from your home’s supply pipes, you may need to hire an expert.

📌 How can you minimize mold growth in your water going forward? The best method is to install a point of use water filter that will remove mold from your water right before you drink it.

The best water treatments for mold are:

  • Reverse osmosis. Reverse osmosis filters are the best defense against drinking mold-contaminated water. An RO system removes all contaminants larger than 0.0001 microns, so it’s capable of mold removal in your water system. By purifying water, reverse osmosis also removes the nutrients that encourage mold to grow. Make sure to replace the filters regularly to prevent mold recontamination.
  • UV purifiers. UV lamps are whole home systems that emit ultraviolet light, which destroys the DNA of microorganisms like bacteria and viruses. UV light has short wavelengths, which makes it effective at destroying mold, too. Most UV purifiers have a lamp lifespan of 1 year.

If you want to reduce your risk of drinking moldy water as much as possible, avoid using countertop gravity filters and pitcher filters, which are most prone to mold accumulation.

Uv purification system

⚠️ How Else Can I Be Exposed to Mold?

Aside from drinking mold in your tap water supply, you might also be exposed to mold in the following ways:

  • By drinking from a reusable water bottle. Metal water bottles might be better for the environment than single-use plastic bottles, but they’re hotspots for water bottle mold if they’re not cleaned regularly. Avoid drinking from a moldy water bottle by thoroughly washing out your water bottle with a bottle brush between every use.
  • By breathing mold spores in the air. If you live in a damp, humid home or work in a damp, humid office, you may be exposed to mold growing on walls, ceilings, and other surfaces. The best mold prevention method for indoor spaces is to install a dehumidifier or an air conditioner to keep your humidity level low.
  • By inhaling mold spores while showering. Most people battle with mold buildup on their showerheads. This report found that 70% of 398 water samples from shower hoses contained mold. Inhaling mold from your shower water is another source of exposure.
  • By being exposed to mold outdoors. Mold is all around us outdoors, even if we can’t see it. Mold can attach to our shoes and clothing, and even our pets, which bring the mold indoors.
  • By ingesting contaminated food. Mold growth on food is usually obvious, but not always. Some foods don’t even have an obvious mold taste when they’re growing mold. Foods most prone to mold growth are jams and jellies, bread, cheese, fruit juices, and nuts.

📝 Where Can I Get More Information?

You can find more information about mold in water and your home, including the common causes and potential health effects, in the links below.