# The Water Supply (Water Quality) (Scotland) Regulations 1990, Schedule 2: SAMPLING FREQUENCIES


TABLE 1:
Sampling frequencies at consumers' taps
Parameters
Water Supply Zone
Sampling Frequency (number per annum)
Volume distributed (m3/d) for domestic purposes
Population Supplied
Reduced
Standard
Increased
Ground water
Surface water
Conductivity or
≤100
≤500
4
12
hydrogen ion
101-1000
501-5000
4
4
6
12
Odour
1001-2000
5001-10000
4
6
12
24
(qualitative)
2001-4000
10001-20000
6
12
24
Taste
4001-7000
20001-35000
11
21
42
(qualitative)
7001-10000
35001-50000
15
30
60
TABLE 2:
Sampling frequencies at consumers' taps
Parameters
Water Supply Zone
Sampling Frequency (number per annum)
Volume distributed (m3/d) for domestic purposes
Population Supplied
Reduced
Standard
Increased
Ground water
Surface water
Odour
(quantitative)
Taste
(qualitative)
Turbidity
≤100
≤500
4
12
Temperature
101-1000
501-5000
4
12
Hydrogen ion
1001-2000
5001-10000
4
24
Nitrate
2001-4000
10001-20000
4
4
6
24
Nitrite
4001-7000
20001-35000
4
5
10
36
Ammonium
7001-10000
35001-50000
4
5
10
48
Ammonium
Iron
Aluminium
Manganese
TABLE 3:
Sampling frequencies at consumers' taps
Parameters
Water Supply Zone
Sampling Frequency (number per annum)
Volume distributed (m3/d) for domestic purposes
Population Supplied
Reduced
Standard
Increased
Notes
(i) ie any fungicide, herbicide or insecticide; increased or reduced sampling, where required or permitted, may be confirmed to the substance in question.
(ii) The sum of the detected concentrations of fluoranthene, benzo 3.4 fluoranthene, benzo 11.12 fluoranthene, benzo 3.4 pyrene, benzo 1.12 perylene and indeno (1,2,3-cd) pyrene.
Trihalomethanes
≤7000
≤3500
1
4
12
Tetrachloromethane
Trichloroethene
Tetrachloroethene
Copper
Lead
7001-10000
35001-50000
1
4
24
Zinc
Pesticides
Polycyclic aromatic hydrocarbons
TABLE 4:
Sampling frequencies at consumers' taps
Parameters
Sampling Frequency
(number per annum)
Standard
Increased
Chloride
Sulphate
Calcium
Magnesium
Sodium
Potassium
Dry residues
Oxidizability
(permanganate value)
Total organic carbon
Boron
Surfactants
Phosphorus
1
12
Fluoride
Barium
Silver
Arsenic
Cadmium
Cyanide
Chromium
Mercury
>Nickel
Antimony
Selenium
Total hardness
Alkalinity
TABLE 5:
Sampling frequencies at supplyh points
Water Supply Zone or Combination of Zones
Sampling Frequency (number per annum)
Volume distributed (m3/d) for domestic purposes
Population Supplied
Table 1 Parameters
Table 2 Parameters
Table 3 Parameters
Table 4 Parameters
Reduced
Standard
Increased
Reduced
Standard
Increased
Reduced
Standard
Increased
Reduced
Standard
Increased
GW
SW
GW
SW
GW
SW
GW
SW
GW = Ground water
SW = Surface water
* Reference is to Tables 1 to 4 of this Schedule
≤100
≤500
4
12
4
12
1
2
4
12
1
12
101-1000
501-5000
4
4
6
12
4
12
1
2
4
12
1
12
1001-2000
5001-10000
4
6
12
24
4
24
1
2
4
12
1
12
2001-4000
10001-20000
6
12
24
4
4
6
24
1
2
4
12
1
12
4001-10000
20001-50000
15
30
60
4
5
10
60
1
2
4
12
1
12
1001-20000
50001-100000
30
60
120
5
10
20
60
2
3
6
24
1
1
2
24
20001-30000
100001-150000
45
90
180
8
15
30
60
2
3
6
24
1
2
3
24
30001-60000
150001-300000
90
180
360
15
30
60
120
2
3
6
24
2
3
6
24
60001-100000
300001-500000
90
180
360
30
60
120
3
5
10
24
3
5
10
24
100001-200000
500001-1000000
90
180
360
30
60
120
5
10
20
36
5
10
20
36
TABLE 6:
Sampling frequencies at consumers' taps
Parameters
Water Supply Zone
Sampling Frequency (number per annum)
Volume distributed (m3/d) for domestic purposes
Population Supplied
Standard
Total Coliforms
≤100
≤500
12
Faecal coliforms
101-1000
501-5000
12
Residual disinfectant
1001-2000
5001-10000
24
Colony counts
2001-4000
10001-20000
48
20001-50000
at the rate of 12 per 5000 population except in the case of colony counts where the standard number is 52
TABLE 7:
Sampling frequencies for treatment works
Parameters
Volume of water supplied (m3/d) for domestic purposes
Sampling frequency (number per annum)
Reduced
Standard
1. Total and faecal coliforms,
≤2000
12
52
residual disinfectant and
2001-6000
52
104
colony counts
2. Total and faecal coliforms
6001-12000
104
208
and residual disinfectant
>12000
104
365
3. Colony counts
>6000
52
104

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Source: https://www.legislation.gov.uk/uksi/1990/119/schedule/2 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-scotland-regulations-1990/schedule-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.