Chloride in Water

Chloride is a naturally occurring element that is often associated with elevated sodium levels in water.

This glossary discusses the risks and effects of drinking water with a high chloride content, how to tell if your water contains chloride, how to protect your family from chloride, and more.

❔ What is Chloride?

Chloride is a transparent, tasteless, odorless, anion (an ion with a negative charge) that forms the element, chlorine.

💡 Chloride occurs naturally, is widely present in the environment, and can be found in various water sources (streams, seawater, groundwater, urban runoff, and wastewater), geologic formations, human blood, and animal waste. Chloride is also present in the form of sodium chloride (salt), which is used for cooking, water treatment, and road de-icing.

Other ions are commonly found alongside chloride, including carbonates, potassium, sodium, and sulfate.

In excess, chloride can weaken metallic fixtures and piping, promoting corrosion, and hinders the growth of vegetation.

🩺 What are the Potential Health Effects of Chloride?

Chloride in water is generally considered safe to drink in low concentrations. Generally, a small amount of chloride may affect water’s taste, but it doesn’t have known health risks.

Chloride is an essential nutrient and maintains a proper balance of fluids in the human body. Most water supplies contain relatively low concentrations of chloride, which makes up a small portion of our daily dietary intake.

Drinking high levels of chloride in water may dangerously increase the chloride concentrations in the blood. This is known as hyperchloremia. Symptoms of hyperchloremia include:

• High blood pressure
• Fluid retention
• Numbness and tingling
• Confusion and personality changes
• Convulsions and seizures
• Muscle twitches, weakness, and spasms
• Excessive thirst
• Dry mucous membranes

The biggest risk of elevated chloride levels is that they’re often associated with elevated sodium levels. According to Healthline, too much sodium chloride in drinking water has the following health concerns:

• High blood pressure
• Increased kidney disease risk
• Increased heart disease risk
• Water retention and swelling
• Dehydration

The potential health effects of sodium chloride depend on the concentrations of chloride in tap water and how much water is consumed.

Sodium chloride is also known to attack metal pipes and plumbing, increasing the likelihood of corrosion. A high concentration of metals in your water supply may cause the following health effects:

• Nervous system disorders
• Kidney dysfunction
• Birth defects
• Immune system effects
• Increased risk of cancer

The types of heavy metals in your water affect the health effects you may experience.

🚰 How Does Chloride Get Into Drinking Water?

Chloride is found naturally in the environment, including in rocks, soils, rainwater, surface water, and groundwater supplies.

Some regions have a higher environmental chloride concentration than others.

For instance, regions with heavy mining and drilling activities, fertilizer use, and road salt application, are likely to have elevated chloride levels in the local water supplies. Coastal regions, and regions with large landfill sites also have more chloride in their surface and groundwater sources.

The most common causes of chloride in surface water and groundwater are:

• Soil weathering
• Deposition of salt spray
• Dissolved salts from geological formations
• Salt used to de-ice roads
• Ocean water intrusion

If water seeps through rocks and soils with high chloride concentrations, some of this chloride will dissolve into the water.

A sudden increase of chloride in your drinking water points to sea water contamination. If you think your well is at risk of sea water intrusion, contact your local well contractor to discuss solutions and preventative methods as early as possible.

Chloride is also added to water intentionally in water softening systems.

A water softener exchanges calcium and magnesium hardness minerals with sodium chloride ions in a process known as ion exchange. Water softeners add only a small amount of sodium to water. If you think your softener is adding too much salt, the system might be malfunctioning or the settings could be wrong.

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

Yes, water treatment facilities monitor levels of chloride in drinking water, but they’re not legally obliged to reduce this contaminant to a certain level.

The Environmental Protection Agency (EPA) lists chloride as a secondary contaminant, which means the rules for treating chloride fall under the Secondary Drinking Water Standards.

These Standards aren’t mandatory because secondary contaminants aren’t considered a threat to human health. Most secondary contaminants have aesthetic issues (such as bad tastes or odors), technical effects (such as damage to water treatment equipment), or cosmetic issues.

Chloride is said to have aesthetic issues because it affects the taste of water. Chloride also has technical effects because it’s known to cause surface staining and corrosion.

📌 The EPA’s Secondary Maximum Contaminant Level for chloride is 250 mg/L.

This MCL is a recommendation to water suppliers, not a legal requirement. That means your local water supply might have higher concentrations of chloride depending on the treatment options used to improve your drinking water quality.

If chloride is found above the SMCL, the EPA notes the most likely effect to be a salty, unpleasant taste.

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

If your water’s chloride concentration is low, you probably won’t know that the contaminant is present.

Most people notice an unusual taste if their water contains 200 to 300 mg/L of chloride. Chloride concentrations of 400 mg/L or higher produce a distinct salty taste.

Aside from taste, you may also notice that your metal pipes and fixtures are corroding quickly as a result of chloride in your water.

Want to be certain whether or not your water contains chloride? You’ll need to get your water tested.

The best way to test your water for chloride is to buy a testing package from a state-certified laboratory. A lab test can provide more thorough test outcomes than any at-home water test. Most labs can test for chloride alone and chloride combined with other ions, such as sodium chloride, calcium chloride, and chloride carbonates.

Lab testing can give you an overall indication of your drinking water quality, which is helpful if you think your water may be contaminated due to an issue with your well’s construction.

If you think your water contains sodium chloride, test for heavy metals, too. Sodium chloride is known to corrode plumbing, increasing the risk of toxic metals leaching into your water.

Most laboratories can deliver test results within one or two weeks of receiving your water sample. If you’re concerned about higher concentrations of chloride in your water, or you think your water’s chloride level has suddenly increased, switch to bottled water while you wait for your test results to be returned.

Just want an idea of your water’s chloride concentration? Check your Water Quality Report.

All municipal water suppliers are required to provide an annual Water Quality Report, or Consumer Confidence Report (CCR), to customers that receive their drinking water.

This report outlines the contaminants present in the source water after treatment. One glance at your CCR should tell you instantly whether or not your water contains elevated levels of chloride.

Keep in mind that CCRs are only relevant to one day out of the entire year, and don’t account for fluctuations in chloride concentrations on a day-by-day basis.

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

Because chloride occurs naturally in the environment, there’s not much you can do to prevent chloride from entering your water supply.

However, you can reduce the chloride concentration in your water, especially if you’re worried about drinking elevated concentrations of sodium chloride or you’re following a low-sodium diet for high blood pressure.

The best short-term solution to protect your family from chloride is to buy bottled water for drinking purposes. Don’t boil your water – it’ll only evaporate some of the water, increasing the relative concentration of chloride.

The best long-term solution to protect your family from chloride in drinking water is to install a water treatment system.

Water treatment systems that can reduce chloride or sodium chloride in water are:

• Reverse osmosis – RO systems use membrane separation to remove the majority of total dissolved solids (TDS), including minerals and salts. Reverse osmosis is a highly effective method of removing sodium chloride, potassium chloride, calcium chloride, and other types of chloride ions, as well as toxic metals, chemicals, microorganisms, and more. A reverse osmosis system is typically installed as a drinking water treatment unit beneath a kitchen sink or on a countertop.
• Anion exchange – Anion exchange is another highly effective method of removing sodium chloride from water. This water treatment process is essentially the reverse of the water softening process. During anion exchange, every chloride ion in water is exchanged with an ion that has the same charge, on a resin bed with an opposite charge. Calcium hydroxide is commonly used to remove chloride ions in anion exchange. If the system is programmed correctly, anion exchange can remove up to 100% sodium chloride from tap water.
• Distillation – A water distiller produces pure, contaminant-free water by the simple processes of evaporation and condensation. Distillers boil water in a boiling chamber, then direct water through a cooling corridor, where it condenses in a separate container. Most contaminants, including minerals and salts, remain in the boiling chamber, where they can be washed away when the system is cleaned. The distillation process is slow, taking around 5 hours to distill 1 gallon of water.

There are no national recommendations for a specific treatment system to remove chloride.

📌 However, it’s advised to choose a system that is NSF/ANSI certified to official Standards for contaminant removal (Standard 58 for reverse osmosis systems, 61 for anion exchange systems, and 62 for water distillers). An official certification gives you peace of mind that a system performs according to industry standards.

After you’ve installed the system, verify its effectiveness by testing your water again. You should notice a big reduction in contaminants, including a reduction in the water’s sodium chloride concentration, and an overall improvement in water quality.

Remember to maintain and clean your water treatment system regularly or as recommended by the manufacturer.

If you get your water from a well, reconstructing your well may reduce chloride levels in your water.

If your well casing is old, cracked, or damaged, impurities may be contaminating your well from the surrounding rocks and soils. Contact a well contractor to perform an inspection of your well and offer their thoughts on the effectiveness of reconstruction in your situation.

⚠️ How Else Can I Be Exposed to Chloride?

In most households, chloride exposure in drinking water is low. Most of our chloride exposure comes from our diet.

Sodium chloride (sodium combined with chloride), is the most common type of chloride anion and is found in a variety of foods, including:

• Sea salt and table salt
• Seaweed
• Tomatoes
• Rye
• Lettuce
• Olives
• Celery
• Ready meals
• Meat products like bacon
• Cheese
• Some tinned vegetables
• Bread
• Savory snacks

Potassium chloride (potassium combined with chloride) is often used as a salt substitute and is found in the following foods:

• Cereals
• Baby formulas
• Meats
• Sports drinks
• Tinned soups
• Savory snack foods, like chips

📌 Most Americans eat too much sodium per day. That’s why, if your water has a salty taste, it’s worth testing it for sodium chloride to avoid further increasing your sodium intake.

The risk of exposure to chloride through skin contact and inhalation are minimal. You may experience skin or eye irritation as a result of direct contact with chloride.

📝 Where Can I Get More Information?

Learn more about chloride in drinking water, including how chloride is formed and the health effects of a high chloride concentration, in the links below.

• EPA: Secondary Drinking Water Standards: Guidance for Nuisance Chemical
• Science Direct: Chloride