Ground water has the following advantages except -

Groundwater sources are wells and springs. Groundwater is the cheapest and most practical means of providing water in small quantities. Groundwater is superior to surface water because It is likely to be free from pathogenic organisms. it usually requires no treatment supply is likely to be ceain even in dry seasons less subject to contamination. The disadvantages are high in mineral content(salts of magnesium and calcium which render water hard) - it requires pumping or some arrangement to lift the water. The hardness of water is caused by salts of calcium and magnesium( calcium bicarbonate, magnesium bicarbonate, calcium sulphate, magnesium sulphate). Park's textbook of Community Medicine.edition 25. page no: 768