Taste and Odor Issues in Water

A look at causes, identification, and treatment.

By Mike Heatwole, MWS

There is nothing more disturbing than turning on the faucet and not being able to enjoy that glass of water.

Whether you are a well owner or city water customer, the bad taste and smells can ruin your day. Dealing with taste and odor problems can be some of the most frustrating problems to resolve as a water professional.

Most of the common contaminants we deal with are aesthetic problems, meaning they cause problems but are generally not health-related. They are factual and scientifically tested, evaluated, and then corrected. You test, the test tells you what’s in your water, then you offer a tried-and-true solution. It is easy to learn to correct these issues.

Taste and odor issues are a personal response (see Figure 1). We are all different. We have a different set of taste buds and what one person finds offensive, another enjoys. Same with smell. What one person enjoys another finds repulsive; these factors are what makes identification and treatment so challenging. Men and women have different frames of reference so many times over there is not even a consensus between
people living in the same dwelling.

The gustatory system, or our sense of taste, occurs when a substance chemically interacts with a receptor cell located in our taste buds, which are in our oral cavity and along our tongue. Thousands of these buds are what allow us to taste.

There are five basic tastes that we can easily identify: sweet, sour, salty, bitter, savory. Other flavor factors can include heartiness, temperature, fat, calcium (chalky), and one we see a lot in water treatment: metallic. Other sensations may include pungency, coolness, numbness, and astringency (dryness).

Our sense of smell is part of our olfactory system (see Figure 2). Our sense of smell helps to detect desirable foods, hazards (bad smells), and pheromones (secreted chemicals). Odor molecules bind to receptors in the nasal cavity and the signals travel to the olfactory bulb, then to the brain for identification,
memory, and emotion.

It has been estimated humans can detect more than 10,000 distinct odors, and females can smell better than their male counterparts. This is why I recommend going with the lady of the house and not the man when dealing with taste and odor issues.

It is important to note that taste and odor work together. We need both to function to make a proper identification. We cannot have one without the other although we tend to separate them when trying to make identification and diagnosis.

In general, most natural tastes and odors are nuisance issues. Many man-made tastes and odors may be a health risk. Any sudden change in the water in taste or smell should serve as a warning sign something may be wrong with the water.

What should water taste like? Water by definition has no taste or smell. It’s what’s in the water that can cause water to smell or have a taste.

Hopefully the taste comes from mineral content or something desirable. Many folks like to add minerals to drinking water to help improve the taste of water. Flavor additives are also popular today. Unless the water is infused with the proper ingredients, then they may only be a marketing ploy. Anything that helps people drink more helps with their daily hydration needs.

When helping customers diagnose their problems, I find the most difficult part is getting them to use good words. The water “stinks” or “tastes bad” are not good descriptive words. Try not to put words in the customer’s mouth (no pun intended). Help provide good words to help them describe the problem to you (see Figure 3). In time and with practice you will learn that certain taste and odor problems can be related
to certain conditions in the water. To do this, we must learn to use good words.

Water in the past used to not be given much thought if it was clear and clean—it was accepted as good. Over time we have learned to identify and use different types of water. We have in a way become “water snobs”. We are blessed to have access to good clean water in our country that much of the world does not get to experience.

Let’s not take that for granted. With that said let’s get into some common issues I see today.

Salty Water

Most waters have some natural sodium in the water. Common causes are malfunctioning water softeners, road salt runoff (big problem), industrial waste, brackish water, and saltwater intrusion along coastal areas.

The best way to reduce salt sodium and chloride is with a reverse osmosis system.

Fishy Smell

This can be caused by certain resins, especially anion resin. Barium, cadmium, and algae blooms can cause smells. Algae blooms have become a bigger problem over the last 40 years due to runoff and increased temperatures.

Again, reverse osmosis or certain carbons can be effective.

Petroleum Smells and Taste

Not as prevalent these days as the past effort to remove underground storage tanks have been successful in reducing or stopping leaks and spills. Pesticides and insecticides are still a major contributor to these smells and taste.

Test water for hydrocarbons and volatile organic compounds if your customers experience any of this petroleum smell or taste. Carbons and reverse osmosis tend to be good solutions to reduce the contaminants.

Sweet Taste

Sweet taste in water can come from high calcium content in the water. pH and alkaline imbalance can cause a sweet taste to the water. Old pipes and water lines are becoming a larger contributor to taste and odor issues due to slow flows, dead ends, leaching, and corrosion.

As we get older so do our systems. It has been estimated that we make our water sweeter as we continue the use of man-made artificial sweeteners. They do not break down in the wastewater process, so they will build up over time—an interesting thought.

Carbons, softening, and correcting the pH alkalinity balance can help restore water back to a normal taste.

Chlorine/Chloramine

This is the top reason people do not like the taste of their drinking water. These are the chemicals most used by the water treatment industry to prevent bacteria in our supply.

These compounds have many side effects which can make water taste bad. Besides making water taste and smell bad, chlorine can cause dry itchy skin, frizzy hair, and deteriorating fixtures.

Chloramine may cause a medicinal taste. Carbon is generally used to remove this from the water either at the point of entry or point of use. Chloramine requires a different carbon than a general granular activated carbon that is used for chlorine due to the ammonia that is added to the water. Check with your supplier to find the best options for each.

Mold

Yes, mold can exist in water supplies and plumbing. It is not common, but it is harder to diagnose. It can be caused by algae blooms and bacterial growth in plumbing lines.

Chlorination and disinfection are ways to remediate the issue. A common mold that shows up in showers, tubs, and around plumbing drains is an airborne bacteria called Serratia marcescens. This leaves a pink color around damp places. This is controlled by a high-grade air cleaner. Often seen as a water problem, it just turns pink when it contacts moisture. Not all water problems are caused by the water itself.

Metallic Taste or Smell

This is a common complaint about well and city water. Usually, it is related to iron of some type in the water or even from the water lines and plumbing itself.

Copper, arsenic, mercury, or manganese can cause a metallic taste and smell as well. Deterioration of old pipes, corrosion, biofilm accumulation, and steel well casing can all contribute to a metallic taste.

Softeners and specialty medias can be used to reduce the metal in the water. Be sure to do a complete water test to find the culprit. Iron-related bacteria can be identified in the back of a toilet tank or with an Iron-Related Bacteria Test.

Sewer Smell

This is usually more of a smell issue. Dry drain lines or standing water in drains can cause a smell like sewer gas.

Broken lines, unclean sink overflows, and even older well pressure tanks may be the cause. Stagnant water in the line (low use) or dead ends in plumbing can be a cause. Supply lines can react to certain compounds and smell. Replace with a different material.

The smell may come from the hot water setting being too low on the water heater thermostat. I have seen raw sewage getting into shallow wells or older non-grouted wells and contaminating the water supply. If a customer says they smell sewage in their drinking water, do not let them drink it until the water has been tested and verified bacteria-free! This is a problem where you do not want to patch the problem. Take the time to root out the cause and correct the issue.

Chlorination and ultraviolet disinfection are two recommended solutions to help maintain bacteria-free water.

Wet Dog

A wet dog-like smell may be indicative of chemicals in the water, bacteria from the water heater, or environmental contaminants may cause the issue. You will want to have a thorough water analysis of the water to determine what the chemical may be so that a proper recommendation for reduction can be offered to your customer. This will need to be looked at carefully.

Burnt Rubber

This smell has begun to be more prevalent in the last five years or so for me. It seems to develop after the installation of a ultraviolet light or new plastic pipes of some type. New pipes are installed with a well pump change-out or remodeling of some plumbing lines with water treatment installed as part of the installation. The complaint sounds like this: “I did not have that smell until you installed the water treatment.”

Everyone assumes the treatment is the cause of the smell. I have found that the equipment is not the cause but mainly comes from the residues off the plastic piping.

The Plastics Pipe Institute has papers addressing these complaints. While the residues are below any toxicity levels (meaning they pass all standards and are deemed safe for use), the human taste and odor capabilities are much more sensitive. Usually these just go away over time, but some people don’t want to wait.

In many cases, chlorination of the plumbing lines will help to dissipate the smell and taste. Sometimes adding a carbon filter is the solution.

Rotten Egg Smell

This is what I call a fan favorite. Hydrogen sulfide is a gas and when you open the faucet, the gas immediately escapes into the air. Usually, we have our head under the shower or in the sink to wash our face and we get interaction with the gas. Hydrogen sulfide comes from many sources; for example, organic decaying matter and mining operations contribute to natural hydrogen sulfide.

If it is coming from the water source, then it will appear in both the cold raw water and the hot water. If it is due to interior plumbing issues, it is not what I call true hydrogen sulfide, but related to other conditions. Sulfide reaction with the anode rod in the water heater is common and can be rectified by using a different anode rod material or the installation of a powered anode rod.

Supply line smells can be corrected by chlorination or simple replacement of the supply line with a different material. Iron bacteria breaking down in the water heater is another common issue and must be addressed by installation of treatment equipment to remove the iron and kill the iron bacteria.

Other Causes

While many times there is a direct correlation to water quality, plumbing issues, piping materials, and a whole array of things that can cause water smells and taste—they may not be a problem at all!

Since the Covid-19 pandemic took place, one of the side effects of the virus has been a short-term or long-term change in the ways people taste and smell things. This has happened to some of my own family members. It is a very real thing to them, but may be different for other household members.

Medications can also alter one’s sense of taste and smell. I have been involved with several cases when a certain medication caused a severe metallic taste for a particular household member. Respiratory infections, allergies, and dementia can all cause a change in one’s sense of taste and smell. These are sensitive issues to explore with your customers, but they are real situations.

Don’t always assume it is an equipment or piping issue. Check with other family members to gauge the severity of the issue, but use finesse and caution with these discussions.

If you receive these types of complaints or questions from your customers, how do you know what to do?

1. Always start with a water test. Test raw, after equipment if installed, and hot water.
2. Get a complete description from the customers using their words. This is most helpful.
3. Install test ports between each piece of equipment to verify water conditions. Flush and disinfect all plumbing lines and look for dead ends or bad materials.

Take your time and be thorough. You will find the issue and then be able to correct the problem and become the hero of the day for your customer.

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Mike Heatwole, MWS, is A. O. Smith/Water-Right regional sales manager in the Mid-Atlantic region who has worked in the water well and water treatment plumbing business for 43-plus years. He holds the Master Water Specialist designation from the Water Quality Association where he is actively involved. Heatwole has served on the Board of Directors for the Virginia Water Well Association for the past 25 years and is a frequent presenter at state, regional, and national water and well conferences. He can be reached at mike.heatwole@aosmith.com.