My water supply

We’re committed to delivering high-quality drinking water to our customers. Each year we carry out thousands of tests on samples we have taken from treatment works, reservoirs and homes across the region. 

The samples we take are analysed in a UKAS accredited laboratory to ensure they comply with drinking water safety standards.

Schedule 1 Parameters

  Units PCV Number of Samples Number of Samples contravening PCV % No. of samples contravening PCV Min Mean Max
Colour mg/l Pt/Co 20 57 0 0 <1.0 1.97 4
Turbidity FTU 4 57 0 0 <0.1 0.13 0.37
Odour Dil Number 0 57 0 0 0 0 0
Taste Dil Number 0 57 0 0 0 0 0
Sodium mg/l 200 10 0 0 12.4 23.43 42.7
Nitrate (as NO3) mg/l 50 10 0 0 14.9 18.91 26.3
Nitrite (as NO2) mg/l 0.1 10 0 0 <0.01 <0.01 <0.01
Nitrate/Nitrite Ratio mg/l 1 10 0 0 0.30 0.38 0.53
Aluminium ug/l 200 57 0 0 6 13.98 124
Iron ug/l 200 57 0 0 <4.00 9.09 68.6
Manganese ug/l 50 57 0 0 <0.90 1.89 11
Copper mg/l 2 10 0 0 <0.008 0.02 0.10
Fluoride mg/l 1.5 10 0 0 0.92 0.98 1.03
Arsenic ug/l 10 10 0 0 <1.0 <1.0 <1.0
Cadmium ug/l 5 10 0 0 <0.12 0.12 0.12
Chromium ug/l 50 10 0 0 <0.5 <0.5 <0.5
Nickel ug/l 20 10 0 0 <0.60 1.01 1.6
Lead ug/l 10 10 0 0 <0.90 1.31 3.8
Antimony ug/l 5 10 0 0 <0.20 0.41 0.7
Selenium ug/l 10 10 0 0 <0.8 <0.8 <0.8
PAH ug/l 0.1 10 0 0 0 0 0
Escherichia coli No./100ml 0 145 0 0 0 0 0
Intestinal Enterococci cfu/100ml 0 10 0 0 0 0 0
Boron mg/l 1 10 0 0 0.05 0.06 0.09
Benzo(a)pyrene ug/l 0.01 10 0 0 <0.003 <0.003 <0.003
Trihalomethanes (total) ug/l 100 9 0 0 46.2 56.66 81.4
Bromate ug/l 10 10 0 0 <0.80 1.07 1.8


Indicator parameters

  Units PCV Number of samples Number of Samples contravening PCV % No. of samples contravening PCV Minimum Mean Maximum
pH   - 57 0 0 7 7.31 7.70
Sulphate (as SO4) mg/l 250 10 0 0 41 51.57 68.1
Ammonium (as NH4) mg/l 0.5 57 0 0 <0.03 <0.03 <0.03
Total coliforms No./100ml 0 145 1 0.69 0 0.01 1
3 day count,22 deg C cfu/ml 100 57 0 0 0 2.39 27
Free chlorine mg/l - 145 0 0 0.03 0.14 0.53
Total chlorine mg/l - 145 0 0 0.03 0.27 0.7
Conductivity uS/cm 2500 57 0 0 139 453.28 576
Chloride mg/l 250 10 0 0 46 54.4 73

* With the exception of the Total coliform parameter all of the samples collected from this zone in 2020 complied with the Water Supply (Water Quality) (Amendment) Regulations 2018. The unsatisfactory sample was resampled and was found to comply with the regulations. Supplies to this zone are fluoridated up to a level of 1mg/l.

Water hardness
Average of Ca Average of Mg mg/l or ppm CaCO3 Degrees Clark (*0.07) Degrees French (*0.10) Degrees German (*0.056)
54.05 12.60 186.8 13.1 18.7 10.5


Water quality terms

Find out what the technical terms used in the water quality reports mean.