The Water Supply (Water Quality) (Scotland) Regulations 2000

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PART V
MONITORING - ADDITIONAL PROVISIONS

Interpretation

11. In this Part, in relation to residual disinfectant or a parameter and the supply of a volume of water within one of the ranges shown in column (3) of Table 3 in Schedule 3 -

"the standard number" means the number shown in column (5) of that Table as applicable to residual disinfectant or the parameter in question by reference to a volume of water within that range; and

"the reduced number" means the number shown in column (4) of that Table as applicable to that substance or parameter by reference to a volume of water within that range.

Sampling for particular substances and parameters

12. For the purposes of establishing the quality of water to be supplied to any of its water supply zones, a water authority shall take, or cause to be taken, and analyse, or cause to be analysed, not less than the number of samples specified in this Part.

Sampling at treatment works

13.–(1) Subject to paragraphs (2), (4) and (6), in each year a water authority shall take, or cause to be taken, from the point at which water leaves each treatment works which serves its water supply zones for analysis

(a) for determining the concentration of residual disinfectant;

(b) for determining whether, in relation to the parameters shown in Table 3 in Schedule 3 as items 2, 4 to 7 and 22 to [27], water meets the specifications for those parameters set out in Schedule 2; and

(c) for testing for compliance with the prescribed concentrations or values for the other parameters mentioned in Table 3 in Schedule 3,

the standard number of samples.

(2) Where in each of two successive years the results of the analysis of samples taken, subject to paragraph (3), in accordance with these Regulations have established—

(a) in respect of the coliform bacteria or E. coli parameter that the maximum concentration has not been exceeded;

(b) in respect of the clostridium perfringens, conductivity or turbidity parameter that the specification has been met;

(c) in respect of the colony counts parameter that there has been no significant increase,

the number of samples to be taken in respect of that parameter in the next following year from the point at which water leaves that treatment works may, subject to paragraph (4), be the reduced number.

(3) Paragraph (2) shall apply

(a) where the following year is 2004, as if for "these Regulations" there were substituted "the 1990 Regulations"; and

(b) where the following year is 2005, as if before "these Regulations" there were inserted "the 1990 Regulations and".

(4) In respect of the coliform bacteria parameter and the E. coli parameter, the reduced number of samples may be taken in accordance with paragraph (2) only if the water authority is of the opinion

(a) that there is no foreseeable risk that the supply will exceed the maximum concentration for that parameter; or

(b) that the treatment works is designed to secure that, in the event of a failure of the disinfection process, water that has not been disinfected cannot enter the supply.

(5) Samples required to be taken by this regulation shall be taken at regular intervals.

(6) Where a particular treatment works is in use for part only of a year, the minimum number of samples to be taken from that works in that year shall bear to the standard number the same proportion as the number of days in that year in which the treatment works have been in use bears to 365, or in the case of a leap year, 366.

Sampling at service reservoirs

14. A water authority shall take, or cause to be taken, from each of its service reservoirs in each week in which the reservoir is in use, one sample for analysis—

(a) for determining the concentration of residual disinfectant; and

(b) for testing for compliance with the parameters E. coli, coliform bacteria and colony counts.

Sampling: new sources

15.–(1) This regulation applies as respects

(a) any source which has not been used for the supply of water by a water authority at any time since 1st January 2004; and

(b) any source which has been so used but not so used for a period of six months preceding the date on which the water undertaker proposes to supply water from it.

(2) A water authority shall—

(a) before it supplies water from a source mentioned in paragraph (1)(a); and

(b) as soon as is reasonably practicable after it has begun to supply water from a source mentioned in paragraph (1)(b),

take, or cause to be taken, in accordance with paragraph (3), such samples of that water as will enable it to establish

(i) whether water can be supplied from that source without contravening section 76A(1) of the Act; and

(ii) the treatment necessary to ensure that section 76A(2) of the Act is complied with in relation to the supply of that water.

(3) Samples shall be taken

(a) in the case of a source mentioned in paragraph (1)(a), in respect of

(i) the parameters listed in Schedule 1 and the indicator parameters in Schedule 2; and

(ii) any other element, organism or substance which, in the opinion of the undertaker, may cause the supply to contravene section 76A(1) of the Act;

(b) in the case of a source mentioned in paragraph (1)(b), in respect of

(i) the parameters listed in Schedule 1 and the indicator parameters in Schedule 2; and

(ii) any other parameter whose concentration or value may, in the opinion of the water authority, have altered since the last occasion on which water from that source was analysed.

Collection and analysis of samples

16.–(1) A water authority shall secure, so far as is reasonably practicable, that in taking, or causing to be taken, handling, transporting, storing and analysing, or causing to be analysed, any sample taken for the purposes of Part IV or this Part of these Regulations, the appropriate requirements are satisfied.

(2) In paragraph (1) "the appropriate requirements" means such of the following requirements as are applicable:-

(a) the sample is representative of the quality of the water at the time of sampling;

(b) the sample is not contaminated when being taken;

(c) the sample is kept at such temperature and in such conditions as will secure that there is no material alteration of the concentration or value for the measurement or observation of which the sample is intended;

(d) the sample is analysed as soon as may be after it has been taken -

(i) by or under the supervision of a person who is competent to perform that task; and

(ii) with the use of such equipment as is suitable for the purpose;

(e) any laboratory at which samples are analysed has a system of analytical quality control that is subjected from time to time to checking by a person who is

(i) not under the control of either the laboratory or the water authority; and

(ii) approved by the Scottish Ministers for that purpose.

(3) A water authority shall maintain such records as are in its opinion sufficient to enable it to establish, in relation to each sample taken for the purposes of Part IV or this Part, that such of the appropriate requirements as are applicable to that sample have been satisfied.

(4) Subject to paragraph (6), for the purpose of establishing, within acceptable limits of deviation and detection, whether the sample contains concentrations or values which contravene the prescribed concentrations or values—

(a) the method of analysis specified in column (2) of Table A1 in Schedule 4 shall be used for determining compliance with the parameter specified in relation to that method in column (1);

(b) the method of analysis used for determining compliance with a parameter specified in column (1) of Table A2 in Schedule 4 must be capable, at the time of use-

(i) of measuring concentrations and values equal to the parametric value with the trueness and precision specified in relation to that parameter in columns (2) and (3) of that Table; and

(ii) of detecting the parameter at the limit of detection specified in relation to that parameter in column (4) of that Table;

(c) the method of analysis used for determining compliance with the hydrogen ion parameter must be capable, at the time of use, of measuring concentrations equal to the parametric value with a trueness of 0.2 pH unit and a precision of 0.2 pH unit; and

(d) the method of analysis used for determining compliance with the turbidity parameter in samples taken from treated surface water must be capable, at the time of use

(i) of measuring concentrations equal to the parametric value with a trueness of 25% and a precision of 25%; and

(ii) of detecting the parameter at a limit of detection of 25% of the parametric value.

(5) In paragraph (4)

"limit of detection" means

(a) three times the relative within batch standard deviation of a natural sample containing a low concentration of the parameter; or

(b) five times the relative within batch standard deviation of a blank sample;

"precision" (the random error) means the standard deviation (within a batch and between batches) of the spread of result about the mean; and

"trueness" (the systematic error) means the difference between the mean value of the large number of repeated measurements and the true value.

(6) Any person may apply to the Scottish Ministers for their approval of a method of analysis other than that specified in paragraph (4)(a) ("the prescribed method").

(7) An application under paragraph (6) shall be made in writing (or in electronic form acceptable to them) and shall be accompanied by

(a) a description of the method of analysis; and

(b) the results of the tests carried out to demonstrate the reliablity of that method and its equivalence to the prescribed method.

(8) The Scottish Ministers shall not authorise the use of the method proposed in the application unless they are satisfied that the results obtained by the use of that method are at least as reliable as those produced by the use of the prescribed method.

(9) An authorisation under paragraph (8) may be subject to such conditions as the Scottish Ministers think fit.

(10) The Scottish Ministers may at any time by notice in writing (or in electronic form) served on the water authority to whom an authorisation under paragraph (8) has been given revoke the authorisation, but no such notice shall be served later than 3 months before the date on which the revocation is stated to take effect.

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