---
title: "Pure/impure, potable/wholesome, polluted/contaminated"
subject: "Water Supply Engineering"
chapter: 1
key: "semester_5/water_supply_engineering:differentiate-water-types"
source: https://www.bctengineer.com/q/semester_5/water_supply_engineering/differentiate-water-types
site: BCT Engineering
---

# Pure/impure, potable/wholesome, polluted/contaminated

Water Supply Engineering · Chapter 1: Introduction

- Asked in: 2074 Asoj, 4 marks
- Video: [Quality of water || Types of water||Impurities in water||pure,wholesome, contaminated water ||Arya](https://www.youtube.com/watch?v=ZFrXDXfN0Qw) — Arya Anjum
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_5/water_supply_engineering/differentiate-water-types
- Whole chapter: https://www.bctengineer.com/md/semester_5/water_supply_engineering/chapter-1

## Question

Differentiate between (a) pure and impure water, (b) potable and wholesome water and (c) polluted and contaminated water.

## Short answer

Pure water contains only H2O and is not found naturally; impure water contains dissolved, suspended or colloidal impurities. Potable water is safe to drink but may have taste/colour problems; wholesome water is also pleasant and has minerals within limits. Polluted water is degraded by waste and may not harm health; contaminated water contains disease-causing organisms or toxic chemicals and is always dangerous.

## Answer

#### (a) Pure and impure water
| Pure water | Impure water |
|---|---|
| Only H2O molecules, no other substance | Contains dissolved, suspended or colloidal impurities |
| Not found naturally; distilled water is the nearest | All natural water (rain, river, well) |
| Tasteless (flat) and lacks essential minerals, so not ideal for regular drinking | May be harmful or harmless |

#### (b) Potable and wholesome water
| Potable water | Wholesome water |
|---|---|
| Safe to drink and not harmful to health | Safe, and also agreeable and suitable for all uses |
| May have colour, odour or taste problems | Free from colour, odour, taste and turbidity |
| Mineral content may exceed the desirable limits | Minerals within permissible limits |
| Mainly health safety | Health safety plus acceptability |

#### (c) Polluted and contaminated water
| Polluted water | Contaminated water |
|---|---|
| Unfit due to wastes (sewage, industrial waste) | Contains harmful germs, toxic chemicals or radioactive matter |
| Pollution is a general degradation of quality | Contamination is a health-related impurity |
| Not always dangerous to health | Always dangerous to health |
| Example: water with oil or detergents | Example: water with E. coli or arsenic |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Pure water is:
   A. Found naturally in rivers
   B. Only H2O molecules; distilled water is nearest
   C. Same as potable
   D. Water with minerals
   Answer: B. Pure water has only H2O and does not occur naturally. (Key point: Pure water)

2. Which is true of potable water but not necessarily wholesome water?
   A. Minerals may exceed desired limits
   B. It is unsafe
   C. It must be colourless
   D. It is distilled
   Answer: A. Potable water is health-safe but may have colour, odour, taste or mineral issues. (Key point: Potable minerals)

3. Which statement is correct?
   A. Polluted water is always dangerous
   B. Contaminated water is never harmful
   C. Contaminated water is always dangerous to health; polluted not always
   D. Both are identical
   Answer: C. Contamination is a health-related impurity so always dangerous; pollution is general degradation. (Key point: Polluted danger)

## Related in Water Supply Engineering

- [Potable, wholesome, polluted, contaminated water](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Apotable-wholesome-polluted-contaminated) — Water Supply Engineering, chapter 1
- [Polluted, contaminated water; function in body](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Adefine-polluted-contaminated-function) — Water Supply Engineering, chapter 1
- [Potable, wholesome water; function in body](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Adefine-potable-wholesome-function) — Water Supply Engineering, chapter 1