AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Potable water: Water of appropriate quality is essential for life.
Water of appropriate quality means water that is safe for its intended use.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 1 of 12
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Water of appropriate quality means water that is safe for its intended use. For drinking, this is potable water: water with sufficiently low levels of dissolved salts and microbes to be safe to drink. Potable water is not pure water in the chemical sense, because it still contains dissolved substances. Different uses need different quality: drinking requires potable water, whereas washing, irrigation and industrial cooling may use lower-quality water. Water for life also includes water for agriculture and sanitation, so appropriate quality depends on the purpose. In the UK, potable water is produced by choosing a suitable source, such as a river, lake or aquifer, passing it through filter beds to remove solids, then sterilising it to kill microbes, for example with chlorine, ozone or ultraviolet light.
What earns the marks
- Potable water is water that is safe to drink, with sufficiently low levels of dissolved salts and microbes.
- Potable water is not pure water because it contains dissolved substances.
- Different uses require different water quality, for example drinking, washing, irrigation and industrial cooling.
- Water of appropriate quality is essential for life because it supports drinking, sanitation, agriculture and industry.
- In the UK, potable water is produced by selecting a source, filtering to remove solids and sterilising to kill microbes.
Common mistakes and how to put them right
Stating that potable water is pure water.
Put it right: Potable water contains dissolved substances and is safe rather than chemically pure.
Confusing sterilising with filtering.
Put it right: Filtering removes insoluble solids while sterilising kills microbes.
Assuming all water uses need drinking-quality water.
Put it right: Appropriate quality depends on the purpose, so irrigation and cooling may use lower-quality water.
Exam tips
- Define potable water in terms of safety and low levels of dissolved salts and microbes, not purity.
- When describing treatment, name the stages in order and state the purpose of each stage.
- Link water quality to a specific use to show why appropriate quality matters.
Try the lesson
The start of the Potable water: Water of appropriate quality is essential for life. lesson, made from checked teaching notes for this specification point.
Have a go first
Which statement best explains why water supplies must be carefully managed?
Listen
Water of appropriate quality means water that is safe for its intended use. For drinking, this is potable water: water with sufficiently low levels of dissolved salts and microbes to be safe to drink. Potable water is not pure water in the chemical sense, because it still contains dissolved substances. Different uses need different quality: drinking requires potable water, whereas washing, irrigation and industrial cooling may use lower-quality water. Water for life also includes water for agriculture and sanitation, so appropriate quality depends on the purpose. In the UK, potable water is produced by choosing a suitable source, such as a river, lake or aquifer, passing it through filter beds to remove solids, then sterilising it to kill microbes, for example with chlorine, ozone or ultraviolet light. A strong answer earns marks for these points. Potable water is water that is safe to drink, with sufficiently low levels of dissolved salts and microbes. Potable water is not pure water because it contains dissolved substances. Different uses require different water quality, for example drinking, washing, irrigation and industrial cooling. Water of appropriate quality is essential for life because it supports drinking, sanitation, agriculture and industry. A common slip: Stating that potable water is pure water. Instead, potable water contains dissolved substances and is safe rather than chemically pure. Exam tip: Define potable water in terms of safety and low levels of dissolved salts and microbes, not purity.
Key words
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Potable water
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Water quality and health
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Uses of water
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Safety and purity
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See every definition
- Potable water
- Water with sufficiently low levels of dissolved salts and microbes to be safe to drink.
- Water quality and health
- Water of appropriate quality is essential for life, as it supports drinking, sanitation, agriculture and industry.
- Uses of water
- Different uses need different quality, so washing, irrigation and industrial cooling may use lower-quality water.
- Safety and purity
- Potable water is not pure water in the chemical sense, because it still contains dissolved substances.
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