The wettest winter on record not only means misery for thousands with flooded homes and businesses, but concerns about the hidden dangers flood waters can bring.
Scientists at the British Geological Survey (BGS) say levels are likely to keep rising even if there is no more rain, as so much water is soaking through the soil.
Groundwater flooding occurs when water seeps up through the ground because the earth is so saturated it cannot hold any more water – which can mean contamination in the water supply from your borehole.
Flood waters contain anything that they have picked up as they flow. At a microscopic level these will include bacteria, which can enter your borehole water supply and consequently become a danger to health.
Under normal circumstances, borehole owners should get their supply analysed and risk assessed annually, but during wet winter months it’s an essential precaution to have it checked regularly – even if your are not located in a direct flooding area.
Common problems can involve colour, odour, taste, pH (acidity or alkaline), dissolved solids, bacteria, metallic deposits, nitrates (particularly in agricultural areas), and water hardness.
Water treatment such as Ultra Violet (UV) purifiers can go a long way to protect users from the consequences of flood or surface water in borehole water supplies, and a borehole chamber and headworks inspection is recommended.
Maximum prescribed concentrations
|Hydrogen ion (pH)||pH units||6.5 to 9.5|
|Ammonium ammonia+ammonium ion||mg/l||0.5||Y|
|Nitrite as NO2||mg/l||0.5||Y|
|Nitrate as NO3||mg/l||50||Y|
|Chloride as Cl||mg/l||250||Y|
|aluminium, total as al||ug/l||200||Y|
|calcuim ,total as ca||mg/l||250||Y|
|Iron, Total as Fe||ug/l||200||Y|
|Magnesium, Total as Mg||mg/l||50||Y|
|Manganese Total Mn||ug/l||50||Y|
|Potassium Total as K||mg/l||12||Y|
|Sodium, Total as Na||mg/l||200||Y|
|Hardness Total as CaCo3||mg/l||Y|
|Total Oxidised Nitrogen as No3||mg/l||50||Y|
|Fluoride,Total as F||mg/l||1.5||Y|
|Lead,Total as Pb||ug/l||10||Y|
|Zinc ,Total as Zn||ug/l||Y|
|Copper ,Total of Cu||mg/l||2||Y|
|Sulphur Total as S04||mg/l||250||Y|
|Alkaninity as CaCO3||mg/l||Y|
|Alkaninity as HCO3||mg/l||Y|
|Total Coliforms confirmed||cfu/100ml||0||Y|
|Escherichia coli confirmed||cfu/100ml||0||Y|
|Total coliform presump||cfu/100ml||0||Y|
|E coli presumtive||cfu/100ml||0||Y|
|TVC 22C 3 day||cfu/100ml||Y|
|TVC 37C 2 day||cfu/100ml||Y|