WHO Water Quality Guidelines: Protecting Public Health

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The World Health Organization (WHO) sets guidelines and parameters for safe drinking water
quality to protect public health. These guidelines aim to ensure that drinking water is free from
harmful contaminants and pathogens. Here are some key parameters outlined by the WHO for
safe drinking water.

WHO water Parameters

1. Microbiological Parameters:

– Total Coliforms: Absence in 100 mL of water
– Escherichia coli (E. coli): Absence in 100 mL of water (indicating fecal contamination)

2. Chemical Parameters:

– Arsenic: ≤ 0.01 mg/L
– Fluoride: ≤ 1.5 mg/L (depending on climate)
– Nitrate: ≤ 50 mg/L (as NO3-)
– Nitrite: ≤ 0.1 mg/L (as NO2-)
– Lead: ≤ 0.01 mg/L

pure water

3. Physical Parameters:

– Turbidity: ≤ 5 NTU (Nephelometric Turbidity Units)
– Colour: Not specified (colour should not be indicative of contamination)
– Odour and Taste: Should be acceptable to consumers

4. Inorganic Chemical Parameters:

– Aluminium: ≤ 0.2 mg/L
– Ammonium: ≤ 0.5 mg/L
– Cadmium: ≤ 0.003 mg/L
– Chromium: ≤ 0.05 mg/L (total)
– Copper: ≤ 2.0 mg/L
– Iron: ≤ 0.3 mg/L

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5. Organic Chemical Parameters:

– Benzene: ≤ 0.01 mg/L
– Carbon tetrachloride: ≤ 0.002 mg/L
– Chloroform: ≤ 0.03 mg/L
– Pesticides: Not specified (should be below levels of concern)
– Polycyclic Aromatic Hydrocarbons (PAHs): ≤ 0.7 µg/L (for benzo[a]pyrene)

6. Radiological Parameters:

– Gross Alpha Activity: ≤ 0.1 Bq/L
– Gross Beta Activity: ≤ 1.0 Bq/L

pure water

7. Disinfection By-products:

– Trihalomethanes (THMs): ≤ 0.08 mg/L
It’s important to note that these are general guidelines, and drinking water standards may vary
based on local regulations and specific conditions. Local authorities may adopt more stringent
standards based on local needs and circumstances. Regular testing and monitoring of drinking
water sources are crucial to ensure compliance with these guidelines and to protect public
health.

For the most up-to-date and comprehensive information on WHO drinking water guidelines, you
should refer to the official WHO guidelines on drinking-water quality.