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Government Of Assam Environment & Forest

Indian Standard Specifications for Drinking Water (IS 10500 - 1983)

  • Sl.
    No.

    Substance or
    Characteristics

    Requirement
    Desirable
    Limit
    Undesirable
    Effect Outside
    the Desirable Limit
    Desirable/
    Essential

    Remarks


    1.Colour, Hazen Units, Max.--Above 10EssentialMay be extended to 50 only if toxic substances are not suspected in absence of alternative sources.
    2.OdourObjectionable--Essentiala)Test cold and when heated.
    b)Test at severaldilutions.
    3.TasteAgreeable--EssentialTest to be conducted only after safety has been established.
    4.Turbidity, NTU, Max.10Above 10, Consumer acceptance decreases.EssentialMay be extended upto 25, in absence of alternative sources.
    5.pH Value6.5 to 8.5Beyond this range the water will affect the mucous membrane and/or water supply system.EssentialMay be relaxed upto 9.2 in absence of alternative sources.
    6.Total Hardness (as CaCO3) mg/l Max.300Encrustation in water supply structure and adverse effects on domestic use.EssentialMay be extended upto 600 in the absence of other sources.
    7.Calcium (as Ca), mg/l, Max.75Encrustation in water supply structure and adverse effects on domestic use.DesirableMay be extended upto 200, in the absence of other sources.
    8.Magnesium (as Mg), mg/l, Max.30Encrustation in water supply structure and adverse effects on domestic use.DesirableMay be extended upto 100, in the absence of other sources.
    9.Copper (as Cu), mg/l, Max.0.05Astringent taste, dis-colouration and corrosion of pipes fittings and utensils will be caused beyond this.DesirableMay be relaxed upto 1.5.
    10.Iron (as Fe), mg/l, Max.0.3Beyond this limit taste/appearance are affected & has adverse effect on domestic uses and water structures, and promotes iron bacteriaEssentialMay be extended upto 1.0 in absence of alternative sources.
    11.Manganese (as Mn), mg/l, Max.0.1Beyond this limit, taste/appearance are affected on domestic uses and water supply structure.DesirableMay be extended up to 0.5 where alternate source is not available.
    12.Sulphate (as SO4), mg/l, Max.250Beyond this causes gastrointestinal irrigation when magnesium of sodium are present .EssentialMay be extended up to 400 provided magnesium (as Mg) does not exceed 30.
    13.Chloride (as Cl), mg/l, Max.250Beyond this limit, taste, corrosion and palatability are affectedEssentialMay be extended up to 1000 in the absence of other alternate sources.
    14.Nitrate (as NO3)mg/l, Max.45Beyond this mathemoglobinaemia takes place.DesirableNo relaxation
    15.Fluoride (as F), mg/l0.6 to 1.2Low floride level are linked with dental carries above 1.5 it may cause fluorosis.DesirableIf the limit is below 0.6 water source should be rejected but suitable public health measures should be taken.Maximum limit may be extended to 1.5 if no better alternate source is available.
    16.Phenolic Compounds (as C6H5OH), mg/l, Max.0.001Beyond this it may cause objectionable taste and odour.DesirableMay be relaxed up to 0.002.
    17.Mercury (as Hg) mg/L, Max.0.001Beyond this the water becomes toxic.DesirableNo relaxation of this limit is allowed to be tested when pollution is suspected.
    18.Cadmium (as Cd), mg/l, Max.0.01Beyond this the water becomes toxic.DesirableNo relaxation of this limit is allowed to be tested when pollution is suspected.
    19.Selenium (as Se) mg/l, Max.0.01Beyond this the water becomes toxic.DesirableNo relaxation of this limit is allowed to be tested when pollution is suspected.
    20.Arsenic (as as) mg/l, Max.0.05Beyond this the water becomes toxic.DesirableNo relaxation of this limit is allowed to be tested when pollution is suspected
    21.Cyanide (as Cn) mg/l, Max.0.05Beyond this the water becomes toxic.DesirableNo relaxation of this limit is allowed to be tested when pollution is suspected
    22.Lead (as Pb), mg/l, Max.0.1Beyond this the water becomes toxic.DesirableNo relaxation of this limit is allowed to be tested when pollution is suspected
    23.Zinc (as Zn), mg/l, Max.5.0Beyond this limit it can cause astringent taste and an opalescence in water.DesirableMay be relaxed up to 10.0. To be tested when pollution is suspected.
    24.Anionic detergents (as MBAS), mg/l, Max.0.2Beyond this limit it can cause a light froth in water.DesirableMay be relaxed up to 1.0. To be tested when pollution is suspected.
    25.Chromium (as Cr+6) mg/l, Max.0.05May be carcinogenic.Desirable--
    26.Mineral Oil, mg/l, Max.0.01Beyond this limit undesirable taste and odour after chlorination takes place.DesirableMay be relaxed up to 0.03. To be tested when pollution is suspected
    27.Residual free chlorine mg/l, Max.0.2--EssentialTo be applicable only when water is chlorinated. Tested at consumer end. When protection against viral infection is required, it should be min. 0.5 mg/L.