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Tap Water for Medical Uses at Home

tap water

Tap Water for Medical Uses at Home

Water from your tap is good for drinking, brushing your teeth, bathing, cooking, and more. It is more economical and better for the environment than bottled water. However there are certain at-home medical uses of water that require extra treatment for tap water or an alternative water source. Research has shown that many individuals are not aware that tap water is not suitable for common medical purposes like contact rinsing, nasal cleaning, and home humidifiers.

Survey of Americans on Tap Water Use

In a survey of 1,004 adults in the U.S., it was found that about one in three people did not think that tap water contained bacteria or other living organisms. About 1 out 4 participants also said that water filters removed microbes and sterilized water, which is not the case. For drinking purposes this is not that important. Water is treated and safe to drink when you get it from the tap even when it contains microorganisms. When it starts to matter is when you are deciding what type of water to use for at home medical purposes.

At Home Medical Uses for Water

These are a few cases where water is used for medical purposes in the home. In all cases there is the concern for infection from using tap water inappropriately but there are other concerns as well.

Nasal rinsing – Saline nasal rinses are used to treat chronic sinusitis, allergy symptoms, and generally for cleaning the nasal passages. Saline nasal rinses require the mixing of salt with water.

Contact lens rinsing – About 45 million people in the U.S. use contact lenses. Contact lenses need to be rinsed thoroughly before they are placed in the eyes.

Home humidifiers – Humidifiers can be used to relieve physical discomforts of dry nose, throat, lips, and skin. The water that is used in humidifiers can affect your health, the particles dispersed in the home, and the longevity of the humidifier.

Concerns with Medical Use of Tap Water

Tap water is safe to drink – as safe as bottled water and much cheaper. (Blind taste tests show that most people cannot differentiate between bottled and tap water). However there can be problems when it is used for medical purposes. When water is entering your body through nose, eyes, and lungs the microbial content of the water needs to be taken into consideration.

Many people do not realize that using tap water for nasal rinsing can be potentially harmful. Tap water is not 100% free of microorganisms. It is clean and safe to drink but not sterile. As water travels through pipes to your home it picks up microorganisms along the way. Your body encounters germs of all types on a daily basis and can easily ingest those found in your tap water. However certain ways that water can enter your body, like through your nose and lungs, have less defense against microorganisms and provide a more direct route to your bloodstream.

Nasal Rinsing

Nasal rinsing is commonly performed to alleviate sinusitis and allergy symptoms and to cleanse the nasal passages. The CDC advises that water used for nasal rinsing and the filling of respiratory devices should be sterile. This can be water that is purchased in bottles labeled distilled or sterile. It can also be made by boiling tap water for 5 minutes and allowing it to cool until it is lukewarm. Tap water can contain bacteria that may stay alive in the nasal passages and result in an infection.

Contact Lenses

Contact lenses should not be in contact with water except when they are being stored or cleaned. This includes avoiding contact with water when swimming and bathing. Cleaning and rinsing of contact lenses should be done with sterile solutions. No contact lens should be placed in the eye that has been cleaned with tap water or any non-sterile liquid. Acanthamoeba is a microbe found in tap water that can attach to a contact lens. If this contaminated contact lens comes in contact with the eye, the eye can become infected.


The high mineral content of tap water can lead to the buildup of scale in a humidifier. Scale can be a good environment for the growth of microorganisms. In addition, the regular use of a humidifier can lead to the development of a “white dust” on surfaces due to the mineral content of the water. There are demineralization cartridges that may be available for some humidifier models that can help reduce the mineral content. However most who use humidifiers for medical uses at home use distilled water. Distilled water will still have some mineral content but generally much less than tap water.

Sources of Medical Use Water

Distilled water can be purchased at most pharmacies or can be purchased online. Be sure to know whether you need to be using sterile or distilled water for your purposes after consulting with your doctor. For certain uses like nasal rinsing with a Rhino Clear atomizer, boiled water may be sufficient. However for ophthalmic applications like contact lenses you should purchase sterile water instead.


Which is better: Bottled water or tap water? – MedicalNewsToday

The Danger of Using Tap Water with Contact Lenses – EPA / Safe Drinking Water Act

Use and Care of Home Humidifiers – EPA / Indoor Air Quality