Potable water is safe to drink, but it’s not pure in the chemical sense. It contains dissolved substances, but in safe amounts for humans.

What is potable water?

• Potable water is clean, safe drinking water
• It contains low levels of salts, microbes, and other contaminants
• It is not chemically pure because it may contain dissolved gases and minerals

💡 Pure water (in Chemistry) only contains H₂O molecules – potable water doesn’t.

Sources of potable water in the UK

1. Rainwater collected in lakes, rivers, reservoirs
2. Groundwater from aquifers

How is potable water produced?

From fresh water (UK method):

1. Filtration – removes solids (sand, twigs, dirt)
2. Sterilisation – kills microbes using:
   • Chlorine, ozone, or UV light

From seawater (desalination):

Used in countries with limited freshwater:

• Distillation – boil and condense water to separate it from salt
• Reverse osmosis – uses membranes to filter out salts

🧪 Both methods are expensive and use lots of energy

Required practical: Testing and purifying water

• Test for pH: potable water should be neutral (pH ~7)
• Test for dissolved solids: boil and see if residue is left
• Distillation can be used to purify water in the lab