Water Taste: Pollutants' Impact And Our Health

Water is an essential resource, and its quality is of utmost importance. While health concerns are a key criterion for judging water quality, taste and odour are also important factors that affect consumer acceptability. Water can take on a range of undesirable flavours, from earthy and metallic to salty and sweet, and these unpleasant tastes often result from elevated concentrations of certain pollutants. For instance, a salt taste in water may be caused by chloride ions and/or sulfates, while a sweet taste can be attributed to high levels of calcium or iron. Other pollutants, such as copper, zinc, manganese, and iron, can impart a metallic taste to water. These pollutants may originate from various sources, including industrial waste, irrigation drainage, and natural sources like seawater intrusion or salt deposits. Identifying and managing these pollutants are crucial to ensuring safe and pleasant-tasting water for consumers.

Chlorinated tap water

Chlorine is added to tap water to eradicate dangerous bacteria and parasites such as legionella, e-coli g, or cryptosporidium. It is also added to public swimming pools to kill microbes, viruses, and bacteria. While chlorine is an incredibly powerful disinfectant, it is also harmful to humans when consumed, even in small amounts.

The chlorine taste in tap water doesn't just mean there's chlorine present; it means there's a harmful amount. The best way to treat chlorinated drinking water is through a multi-stage filtering process. Distillation with activated carbon filters can remove up to 99% of chlorine from tap water. Boiling water for 5-15 minutes or placing it in the refrigerator for 24 hours can also remove the chlorine taste.

Small amounts of chlorine (levels below 4 PPM) are not harmful to health. Levels of free chlorine in public water supplies are typically between 0.5 and 2.0 PPM. However, chlorine can be smelled (and often tasted) at just 1 PPM.

Salty water

Natural Causes of Salty Water

Additionally, sulfates, such as magnesium and sodium sulfate, can occur naturally in soil and rocks. As groundwater or rainwater moves through the earth, it can pick up these sulfates and carry them into the local water supply.

Human-Related Causes of Salty Water

Industrial waste and irrigation drainage are common human-related causes of high chloride levels in water. Furthermore, water softeners use sodium to neutralise minerals in hard water, which can lead to a salty taste if the system is not properly balanced.

Health Effects of Consuming Salty Water

While slightly salty water is generally considered safe to drink and does not impact human health, it is recommended that individuals with high blood pressure, diabetes, and heart disease minimise their consumption of such water.

Remedies for Salty Water

To address salty water, you can employ various methods:

• Install a water purifier or a whole-house reverse osmosis water filter to effectively remove the salty taste.
• Use alum to remove saltiness and purify well water. Alum produces positively charged aluminium hydroxide colloidal particles that attract negatively charged sediment, causing them to sink to the bottom, leaving clear and clean water.
• Treat the water with a reverse-osmosis filter, which pushes water through semi-permeable membranes to remove excess salt.
• If using a water softener, ensure it is functioning properly by checking the control settings, inspecting for clogs, and maintaining the regeneration cycle.

Metallic taste

A metallic taste in water is usually a sign of either a high concentration of iron or a low pH. If the metallic taste is caused by high iron levels, you will likely see iron/rust staining around drains. A low pH, on the other hand, may cause blue-green staining around fixtures.

Causes of Metallic Taste in Water

Old, Rusty City Pipes or Older Residential Plumbing

City water in the US often travels through miles of underground metal pipes, some of which were installed as early as the 1800s and have seen little to no repairs or replacements. As a result, many of these pipes are old, worn out, and deteriorating. When acidic water (water with a pH below 7) comes into contact with these pipes, they start to rust, causing them to dissolve metals like lead, copper, zinc, and iron into the water supply. This phenomenon is known as leaching, and it directly introduces bits of metal into your water as it travels to your home.

High Metal Content

The presence of certain trace metals, especially in well water, can also give water a metallic taste. Groundwater, which comes from underground, passes through layers of soil, sand, minerals, and rocks, picking up various naturally occurring metals like iron, manganese, copper, and zinc, which can impart their undesirable metal-like flavours.

High Chlorine Levels

Compounds like chlorine and chloramine, which are often added to public water supplies to kill microorganisms, can also dissolve metals from pipes and plumbing, causing the water to taste metallic over time.

Low pH

The pH of water can also contribute to a metallic taste. The pH scale ranges from 0-14, with 7 being neutral. The lower the pH, the higher the acidity, and the more metallic the water is likely to taste. Purified water usually has a pH of 6.5-8, giving it a mild flavour. However, when the pH decreases, the water becomes more acidic and corrosive, wearing away metal pipes and plumbing components and dissolving materials like iron, manganese, lead, copper, and zinc. These metals can then leach into the water supply, giving it a metallic flavour.

Health Risks of Drinking Water with a Metallic Taste

While a metallic taste in water is often not harmful, certain minerals and metals that cause this taste can be detrimental to health if ingested frequently.

Lead

According to the CDC, there is no safe level of lead in water. Children are especially vulnerable to its destructive effects, as their bodies absorb more of the metal, and their developing brains may be permanently damaged. Lead can also be dangerous for pregnant women, who can pass it to their unborn babies.

Copper

Small amounts of copper are considered safe and even essential for health. However, excessive copper consumption can lead to short-term symptoms such as diarrhoea, fever, headaches, abdominal cramps, blood in vomit, and weakness. Prolonged exposure to high copper levels has been linked to brain damage, liver damage or failure, kidney problems, heart failure, abnormalities in red blood cells, and an increased risk of cardiovascular disease.

Iron

While some dietary iron is healthy, excess iron consumed through contaminated water can lead to health problems, including nausea, vomiting, diarrhoea, stomach pain, and even organ damage over time, depending on the level and duration of exposure.

Resolving Metallic Taste in Water

If you're dealing with metallic-tasting water, there are several steps you can take to resolve the issue:

Test Your Water

Get your water tested by a professional to identify the specific contaminants and determine the underlying cause of the metallic taste. This is especially important if your household includes pregnant women, infants, children, or individuals with compromised immune systems, as certain heavy metals pose higher risks to these groups.

Flush Your Pipes and Faucets

Run your taps for 15-30 seconds before using the water for drinking or cooking to clear out stagnant water that has accumulated metals. This brings in fresh water from the main supply line, minimising contact time with your home's internal plumbing and reducing the metallic taste.

Clean Your Faucet Aerators

Faucet aerators are small screens at the tip of your faucets that mix air into the flowing water to prevent splashing. Metal particles can become trapped in these aerators and eventually dislodge when you turn on the faucet, releasing high concentrations of metals into the water. Remove and clean or replace your faucet aerators every few months to prevent this buildup.

Install a Water Filter

Filtering your drinking water can effectively reduce dissolved metals and other contaminants affecting its taste. Under-counter water filter systems are a good option if you only want filtered water from your kitchen faucet. These systems often use reverse osmosis to eliminate various metals and chemicals from the water.

By addressing the potential causes of metallic-tasting water and implementing appropriate solutions, you can ensure that your water is not only clean but also tastes great.

Sulphuric water

Health Effects

High levels of sulphur in water can cause dehydration and other gastrointestinal issues, especially in infants. According to the Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC), drinking water with high levels of sulphur can cause diarrhoea.

Effects on Plumbing

Treatment Options

There are several options for treating sulphuric water:

• Aeration: Adding air to well water before it enters the home can help reduce levels of hydrogen sulphide.
• Chlorination: Chlorine bleach can react with hydrogen sulphide and destroy the odour.
• Iron removal filter: An iron removal filter can chemically react with hydrogen sulphide and turn it into insoluble sulphur, which can then be filtered out.
• Neutra Sul: A stable hydrogen peroxide product that can counteract unpleasant sulphur smells and contaminants.

Earthy taste

An earthy taste in water is often caused by dissolved solids, which may be the result of decaying organic matter in the plumbing or the source water itself. A likely culprit is geosmin, a naturally occurring chemical compound produced by bacteria found in soil and algae in local water sources. Although harmless, geosmin is detectable by humans in very small amounts and can give water an overpowering dirt-like taste. The problem is more likely to occur in the summer when algal blooms are more common in local water sources such as lakes, ponds, and rivers.

If you suspect geosmin is the cause of the earthy taste, contact your local water treatment centre. While the issue may not be localised, they may be able to advise on possible solutions. These include using a carbon filter, investing in a reverse-osmosis water-treatment system, or cooling your water in the fridge (as colder water makes taste buds less receptive to the flavour of geosmin).

Another potential cause of earthy-tasting water is bacteria growth in your plumbing, particularly near the exit point (i.e. your faucet or tap). To check if this is the issue, test the water from different taps in your house, including an outdoor hose. If the problem is localised to a single source, try cleaning your faucet by removing the aerator and soaking it in vinegar. You can also clean the inside of the faucet pipe with a microfiber cloth.

In some cases, an earthy taste in water may be caused by actual soil and organic matter from your water source, especially if you have well water or live in an older home with clay or galvanised pipes. To remove particulates, you can use a clip-on tap filter or install a whole-house filter to remove sediment.

Finally, an earthy taste in water could be caused by deposits of heavy metals from the soil or old plumbing. Metals such as iron, copper, zinc, and manganese can cause water to taste earthy, even if they are only present in trace amounts. While these metals are usually not concentrated enough to harm your health, it is recommended that you get your water tested if you notice an earthy taste with metallic undertones, especially if you have well water.

Frequently asked questions