Aesthetic/acceptability limit — chloride in public water supplies: According to common drinking-water acceptability guidelines, the chloride content of treated water supplied to the public should not exceed

Introduction / Context:
Chloride in drinking water is primarily an aesthetic parameter affecting taste and potential corrosivity. While not typically a direct health concern at common levels, higher chloride concentrations can impart a salty taste and accelerate corrosion of metallic distribution systems.

Given Data / Assumptions:

• Standard public-supply acceptability limits are considered (taste/corrosion oriented).
• Units are mg/L = ppm for dilute aqueous solutions.

Concept / Approach:
Many design guides and standards list an acceptable upper limit of approximately 250 mg/L for chloride in public water supplies to minimize taste complaints and material degradation. This value aligns with aesthetic guidelines and is commonly used in examination contexts for water-quality planning.

Step-by-Step Solution:

Verification / Alternative check:
Taste thresholds vary with cation (NaCl vs CaCl2) and consumer sensitivity; however, 250 mg/L is the widely cited benchmark for distribution acceptability.

Why Other Options Are Wrong:
100–200 ppm are more stringent than typical guideline and may be unnecessarily restrictive; 300 ppm risks taste complaints and increased corrosion.

Common Pitfalls:
Confusing chloride with free chlorine residual; mixing TDS limits with single-ion guidelines; overlooking that corrosion index depends on chloride, sulphate, alkalinity, and pH together.

Final Answer:
250 ppm