Cleaning Water: Making water safe at home, at work and in agriculture

Water analysis

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

Test Description Units Limit Accreditiation
Hydrogen ion (pH) pH units 6.5 to 9.5
Conductivity Us/cm 2500 Y
Turbidity NTU 4 Y
Colour mg/l pt/co 20 Y
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