The maximum permissible total dissolved solidcontent in water for domestic purposes should not exceed
- A300 mg/l
- B400 mg/l
- C500 mg/lCorrect
- D1000 mg/l
Solution
Concept
The desirable (acceptable) limit of total dissolved solids (TDS) in drinking water is 500 mg/l.
Step-by-step solution
1. TDS is the total amount of salts and minerals dissolved in water. 2. As per IS 10500, the acceptable limit of TDS is 500 mg/l. 3. A higher limit (2000 mg/l) is allowed only when no other source is available. 4. Among the options, the standard answer is 500 mg/l, which is option C.
Explanation
High TDS gives water a salty taste and can cause scale. For domestic use, TDS should normally not exceed 500 mg/l.
Why the other options are wrong
A and B (300 and 400 mg/l) are lower than the standard limit. D (1000 mg/l) is higher than the acceptable limit and is not the usual exam answer.
Shortcut
TDS limit: 500 desirable, 2000 permissible when there is no alternate source.
Common mistake
Choosing 1000 or 2000 mg/l by thinking of the relaxed limit used when no alternate source exists.
Correct answer: C) 500 mg/l