<prompt> Ground water has the following advantages exceptLikely to be free from pathogenic organismsUsually requires no treatmentSupply is likely to be certain even during dry seasonLikely to be hard  <response>: Ground water is hard, but it is a disadvantage not advantage.Ground waterGround water is the cheapest and most practical means of providing water to small quantities.Ground water is superior to surface water, because the ground itself provides an effective filtering medium.AdvantagesIt is likely to be free from pathogenic agents.Requires no treatment disinfection.The supply is likely to be certain even during dry season.It is less subject to contamination than surface water.DisadvantagesIt is high in mineral content e.g., salts and magnesium which render the water hard.It requires pumping or some arrangement to lift the water. 