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 54 0 0 <1.00 <1.00 <1.00
Turbidity FTU 4 54 0 0 <0.10 0.14 0.63
Odour Dil Number 0 54 0 0 0 0 0
Taste Dil Number 0 54 0 0 0 0 0
Sodium mg/l 200 10 0 0 8 10.37 13.30
Nitrate (as NO3) mg/l 50 10 0 0 35.90 38.05 40.70
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 0.72 0.76 0.82
Aluminium ug/l 200 10 0 0 <6.00 <6.00 <6.00
Iron ug/l 200 10 0 0 <4.00 <4.00 4.60
Manganese ug/l 50 10 0 0 <1.70 <1.70 <1.70
Copper mg/l 2 10 0 0 <0.008 0.06 0.20
Fluoride mg/l 1.5 10 0 0 0.14 0.16 0.19
Arsenic ug/l 10 10 0 0 <1.00 <1.00 <1.00
Cadmium ug/l 5 10 0 0 <0.12 <0.12 <0.12
Chromium ug/l 50 10 0 0 <0.50 0.51 0.60
Nickel ug/l 20 10 0 0 <0.60 3.07 13.4
Lead ug/l 10 10 1 10 <0.90 3.67 28
Antimony ug/l 5 10 0 0 <0.20 <0.20 <0.20
Selenium ug/l 10 10 0 0 <0.80 0.83 1.00
PAH ug/l 0.1 10 0 0 0 0 0
Escherichia coli No./100ml 0 191 0 0 0 0 0
Intestinal Enterococci cfu/100ml 0 10 0 0 0 0 0
Boron mg/l 1 10 0 0 <0.04 <0.04 <0.04
Benzo(a)pyrene ug/l 0.01 10 0 0 <0.003 <0.003 <0.003
Trihalomethanes (total) ug/l 100 10 0 0 0 3.43 8.10


Indicator parameters

  Units PCV Number of samples Number of Samples contravening PCV % No. of samples contravening PCV Minimum Mean Maximum
pH (New Reg Limit) Env   - 54 0 0 7.20 7.35 7.70
Sulphate (as SO4) mg/l 250 10 0 0 26.10 27.86 29.50
Ammonium (as NH4) mg/l 0.5 54 0 0 <0.03 <0.03 <0.03
Total coliforms No./100ml 0 191 0 0 0 0 0
3 day count,22 deg C cfu/ml - 54 0 0 0 5.81 300
Free chlorine mg/l - 191 0 0 0.03 0.09 0.19
2 day count,37 deg C cfu/ml 10 2 0 0 0 0 0
Conductivity uS/cm 2500 54 0 0 527 563.76 718
Chloride mg/l 250 10 0 0 21 31.4 42

* All of the samples with the exception of the Lead parameter 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.

Water hardness
Average of Mg Average of Ca mg/l or ppm CaCO3 Degrees Clark (*0.07) Degrees French (*0.10) Degrees German (*0.056)
3.94 113.80 300.4 21.0 30.0 16.8


Water quality terms

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