My tap water smells! What your water is trying to tell you

As Canadians, we expect to have clean, running water at our fingertips, so the slightest smell or weird colour sets off alarm bells. Here's some advice to help you pinpoint the problem, determine if it's merely a nuisance or dangerously nasty, then figure out a solution.

Safe drinking water is a shared responsibility between the provincial, territorial, federal and municipal governments, according to Health Canada. But once that water enters your home’s plumbing system, “It is the full responsibility of a homeowner to make sure water in every tap is safe to drink,” explains André St-Denis, CEO of AquaWaterEau Corporation.

As Canadians, we’re accustomed to having fresh, clean water at our immediate disposal. That’s why when our tap water smells strange or has a funny colour, we find it alarming.

If you’re a homeowner in this situation, what can you do? There are a few home tests you can use to discover the cause of the problem and how to possibly solve it.

“When your water smells, until you investigate and cure the problem, buying a bottle of water is a short-term, temporary solution,” says St-Denis. In terms of a long-term solution, he recommends getting to the source of the odour.

Before you can remedy your problem, you need to know where it’s coming from. A good place to start is by checking your taps.

• If water from all the faucets in your home smell, chances are the main water supply is the culprit.
• If only certain faucets smell when turned on, it could mean only those specific fixtures or pipes are affected.

You should also consider how long the odour persists.

• If the smell goes away after running the water for a few minutes, this suggests an issue with the household plumbing system.
• If the odour won’t go away, there could be a problem in the water source, or a combination of the water source and plumbing system.

The types of odours emanating from your tap water are typically a good indicator of what’s causing the issue. Some of the more common odours and what they might mean include:

Symptoms
Tannins produce an aromatic, earthy or woody smell that is present in surface waters. They also tend to darken the water’s colour, from light-yellow to brown. In most cases, tannins will not form the kind of stain deposits that are hard to clean and remove, like those produced by such metals as iron and manganese. However, tannins may still leave behind slimy films that, although generally easy to scrub off, are still unpleasant.

Cause
Due to the natural process of decomposition and decay of organic matter, such as soil and leaves.

Health risks
St-Denis adds that tannins on their own in drinking water are rarely dangerous. Nonetheless, it’s still important to seek help from a professional with access to specialized equipment and expertise to solve the problem. Why?

“For aesthetic reasons, nobody these days wants tap water the colour of tea or apple juice. Not only does it look awful, but it can stain laundry and affect the taste and colour of food,” explains St-Denis. “What’s more, the real concern with tannins in drinking water is that because tannins are organic, they serve as food for bacteria and other microorganisms, which can multiply and grow. By themselves, tannins may not be dangerous but they can create other problems that are.”

Treatment
A professional will likely use an activated carbon filter, activated carbon cartridge filter, reverse osmosis or anions resin.

Symptoms
Strong chlorine smell.

Cause
This smell might be due to excessive concentrations of chlorine in the water after treatment by a municipality or private residence.

Health risks
Apart from the unpleasant taste and odour, short-term consumption rarely poses health risks to the homeowner. However, when someone has been exposed to long-term consumption of chlorine, many studies and experts suggest that it significantly increases people’s risks of developing serious health problems.

Treatment
An activated carbon filter can typically take care of the issue through reverse osmosis.

For drinking water applications, St-Denis. says, “Reverse osmosis is recognized as the preferred method because it combines an activated carbon filter plus a semi-permeable membrane to help remove most other impurities as well.”

Symptom
Rotten egg smell.

Cause
The rotten egg smell is likely the result of interactions between sulfates and bacteria in untreated water. If the smell only occurs when the hot water is running, the magnesium rod in your hot water heater could be reacting with the water. As a result, along with the unpleasant odour, it can also tarnish cutlery. What’s more, you may also notice yellow and black spots on plumbing fixtures.

Health risks
The unpleasant smell can change the taste/colour of certain foods and drinks, but doesn’t appear to pose any health hazards.

Treatment
Depending on the situation, St-Denis suggests hiring a professional to help address the problem using various filters and methods to disinfect the entire plumbing system.

Symptom
Strong detergent smell.

Cause
This smell, along with water that foams when running, is typically because of a septic tank installation “sweating” and infiltrating the subterranean water table.

Health risks
Drinking this water could expose you to gastrointestinal illnesses and result in symptoms such as diarrhea, vomiting and cramps – especially dangerous to babies, elderly people and people who already have a weak immune system.

“Detergent in your water is dangerous because it’s a clear indication that your septic tank is not performing well, resulting in septic water leakage into your well,” says St-Denis. “Any change in the water smell after it rains or snow melts is a clear indication that surface water is entering the well. Don’t take any risks because E. coli is deadly.”

Treatment
Homeowners must find and eliminate the source of the infiltration immediately. After the problem of infiltration is fixed, shock chlorinating* the well and/or distribution plumbing could potentially resolve the problem.

*N.B.: Because the shock chlorination process is complicated, it should be done by a licensed professional with the proper equipment and experience to do the job safely – one who understands the precautions that must be taken during the chlorination procedure.

Symptom
The pungent smell of gasoline coming from running water.

Cause
This smell probably means a gas or oil tank has leaked into the water distribution system or aquifer.

Health risks
Drinking this water can cause serious health problems like anemia, liver and kidney issues, and an increased risk of cancer. If detected, the homeowner should take immediate action.

Treatment
Homeowners should start by trying to find and eliminate the source of the infiltration, which is much easier if it is located on the homeowner’s property. If the source is located far away, you may need to work with a professional. After identifying the cause of the infiltration, shock chlorinating the well and/or distribution plumbing may potentially remedy the situation.

N.B.: In some instances, if the groundwater contamination is deemed too extensive to clean up by a professional, you may be legally required to call Environment and Climate Change Canada for further assistance.

Symptom
A methane smell that produces cloudy water.

Cause
This could come from an abandoned landfill site or an oil field, often produced by organic material that is decomposing underground.

Health risks
You should avoid this water as the gas is explosive and toxic to breathe.

Treatment
An atmospheric ventilation system designed by a water treatment expert can help to eliminate gases, tastes and smells.

Symptom
A smell of phenol (sometimes described as tarry, other times the smell of decay) or other chemical odours in your water.

Cause
This suggests pesticides, herbicides or other chemicals used for agricultural or industrial purposes could have leaked into the water distribution system or aquifer that feeds into your house.

Health risks
Drinking this water can lead to health problems including anemia, nervous system issues or reproductive disorders. It may also increase the risk of cancer, stomach, liver and kidney diseases.

Treatment
St-Denis recommends hiring a professional as highly sensitive equipment will likely be required to detect the issue and help solve the problem.

Since many other water problems may not have an easily detectable smell, St-Denis says it’s crucial for well owners to have their water professionally tested each year.

“It is the full responsibility of a homeowner to make sure water in every tap is safe to drink,” he says, adding that a homeowner could possibly be held responsible if a visitor gets sick from something he or she picked up from the water.

If you’re concerned your water might be hiding something potentially harmful to consume, call your local health department or a water treatment expert for help before a small issue becomes something bigger.