Water Quality
Water quality is an issue that comes up with increasing frequency, both in the media and in personal conversations. More and more, we wonder about the quality of the water we drink every day. This article focuses on the following questions:
- What is "good water"?
- What are the main problems, regarding water quality?
- How is water quality measured?
- How is water quality protected?
- How can I find out about the quality of my water?
- What about bottled water?
- Where can I find more information?
What is "good water"?
Depending on your geographical location, drinking water is either:
- Surface water (rivers, streams and lakes)
- Ground water (aquifers)
In a very general sense, water is "good" when it's suitable for drinking and can sustain aquatic life. Water quality varies according to location, season, climate and types of soils. It can be influenced by a number of natural processes.
For example, water:
- dissolves minerals by moving through rocks and soil
- carries organic material, as well as well as sand, silt and clay, as it flows
- reacts with algae, bacteria and other microscopic organisms
- evaporates thereby producing more concentrated dissolved minerals
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What are the main problems regarding water quality?
Many problems can occur, both from natural and human causes:
- Natural alterations Water naturally contains dissolved substances, minerals or salts, including:
- Common constituents (e.g. calcium, sodium, bicarbonate and chloride) that can affect water's taste, clarity and smell
- Trace elements (e.g. selenium, chromium and arsenic) that can become hazardous beyond certain amounts
- Human alterations A number of human activities can influence water quality:
- Urban development
- Industrial development
- Mining
- Fossil fuels
- Stream-channel alteration
- Animal-feeding operations
For example, plant nutrients like nitrogen and phosphorus fertilizers that are used on crops and lawns, can constitute a hazard because they:
- Dissolve in rainwater or snowmelt runoff
- Trickle into streams and lakes
- Encourage growth of algae which leads to low oxygen levels that threaten aquatic life
Source water is particularly vulnerable. It can be "naturally" contaminated by animal fecal matter, algal growth or geologic formations. Even if protecting source water does not entirely prevent contamination problems, it is a key to eliminating contamination.
Surface water is also vulnerable to human-made contamination from:
- point sources (e.g. pipes or man-made ditches that transport discharge pollutants)
- non-point sources (e.g. run-off from streets and farmland)
In the US, the Clean Water Act has cut into point source contamination even if non-point sources remain a significant threat.
Chemicals, such as pharmaceutical drugs, dry-cleaning solvents and gasoline, find their way into streams and ground water. Today, pesticides are widespread in streams and ground water though they rarely exceed the existing standards and guidelines established to protect human health.
Pesticides can sometimes be detected in fish and streambed sediment at levels that pose a potential risk to human health, aquatic life and fish-eating wildlife some 20 or 30 years after their use. Also, water typically contains mixtures of chemicals, although regulations have not yet been established for chemical mixtures.
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How is water quality measured?
To establish water quality, scientists generally measure and analyze characteristics such as:
- Temperature
- Dissolved mineral content
- Bacteria
- Turbidity
- Acidity (pH)
- Dissolved oxygen (DO)
- Chemicals
Certain aspects of water quality can be determined on site like temperature, acidity (pH), dissolved oxygen and electrical conductance (which indirectly indicates the presence of dissolved minerals). Analyses of individual chemicals are generally done in laboratory.
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How is water quality protected?
 In Canada, the day-to-day responsibility of providing safe drinking water to the public generally rests with the provinces and territories while municipalities usually oversee the day-to-day operations of the treatment facilities.
In the US, the Environmental Protection Agency (EPA) has established maximum contamination levels (MCLs). Furthermore, the states themselves can set and enforce their own standards if they match or exceed federal levels. However, authorities fully regulate only the drinking water supplied by public water systems – not private wells or bottled water.
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How can I find out about the quality of my water?
In the US, right-to-know provisions under the Safe Drinking Act mean that tap water suppliers must provide citizens with annual water quality reports. You can contact your water utility for a copy of the annual water quality report. Then you might want to download a brochure called "Making Sense of Your Right to Know Report." In Canada, contact your local water supplier, your municipal services or your provincial Ministry of Health or Environment.
What about bottled water?
Bottled water seems to be the obvious, trouble-free solution. Just pay about 2,000 times more for your water and voilà, pure water to go, right? Wrong. Unfortunately, an abundance of studies show that this is often an illusion.
- In 2008, the University of Iowa Hygienic Laboratory conducted analyses on 10 brands of bottled water revealing the presence of a range of pollutants including:
- Disinfection by-products
- Common urban wastewater pollutants, e.g. caffeine and pharmaceuticals (Tylenol)
- Heavy metals and minerals including arsenic and radioactive isotopes
- Fertilizer residue (nitrate and ammonia)
The Environmental Working Group (EWG), the US association that ordered the research, recommends filtering tap water. Carbon filters, for example, remove many of the contaminants found in public tap water supplies and they are typically far less expensive than bottled water. More on EWG's bottled water study.
- Also, producing and transporting water bottles consumes approximately 17 billion barrels of oil a year – enough to fuel 1,000,000 American cars for 12 months – and generates about 2.5 million tons of carbon dioxide. Read more.
- As if that wasn't enough, research also suggests that the plastic in water bottles could be cause for concern. Phthalates – chemicals known to disrupt testosterone and other hormones – can leach into bottled water over time. US regulatory standards limit phthalates in tap water, but there are no legal limits for phthalates in bottled water.
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Where can I find more information?
Learn more about water filters, bottled water, water quality and drinking water and your health.
- Water filters
- Bottled water
- Water quality
- What can I do to improve water quality?
- Drinking water and your health
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