Search Legislation

The Private Water Supplies (Wales) Regulations 2017

What Version

 Help about what version

Status:

This is the original version (as it was originally made). This item of legislation is currently only available in its original format.

Analysing samples: chemical and indicator parameters

3.—(1) On or before 31 December 2019, the local authority may apply the method of analysis for chemical and indicator parameters in either sub-paragraph (3) or sub-paragraph (4).

(2) After 31 December 2019, the local authority must apply the method of analysis for chemical and indicator parameters in sub-paragraph (4).

(3) For each parameter specified in the first column of Table 2 in Part 2 of this Schedule the method is one that is capable of—

(a)measuring concentrations and values with the trueness and precision specified in the second and third columns of that table, and

(b)detecting the parameter at the limit of detection specified in the fourth column of that table.

(4) For each parameter specified in the first column of Table 3 in Part 2 of this Schedule the method is one that is capable of measuring concentrations equal to—

(a)the parametric value with a limit of quantification of 30% or less of the relevant parametric value (as contained in Schedule 1), and

(b)the uncertainty of measurement in the second column of that table.

(5) The method of analysis used for odour and taste parameters must be capable of measuring values equal to the parametric value with a precision of 1 dilution number at 25°C.

(6) For these purposes—

(a)“limit of detection” is—

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

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

(b)“precision” (the random error) is twice the standard deviation (within a batch and between batches) of the spread of results about the mean. Acceptable precision is twice the relative standard deviation. Further specifications are set out in ISO 17025;

(c)“trueness” (the systematic error) is the difference between the mean value of the large number of repeated measurements and the true value. Further specifications are set out in ISO 17025;

(d)“uncertainty of measurement” is a non-negative parameter characterising the dispersion of the quantity values being measured, based on the information used.

Back to top

Options/Help

Print Options

Close

Legislation is available in different versions:

Latest Available (revised):The latest available updated version of the legislation incorporating changes made by subsequent legislation and applied by our editorial team. Changes we have not yet applied to the text, can be found in the ‘Changes to Legislation’ area. The revised version is currently only available in English.

Original (As Enacted or Made) - English:The original English language version of the legislation as it stood when it was enacted or made. No changes have been applied to the text.

Original (As Enacted or Made) - Welsh:The original Welsh language version of the legislation as it stood when it was enacted or made. No changes have been applied to the text.

Close

Opening Options

Different options to open legislation in order to view more content on screen at once

Close

More Resources

Access essential accompanying documents and information for this legislation item from this tab. Dependent on the legislation item being viewed this may include:

  • the original print PDF of the as enacted version that was used for the print copy
  • lists of changes made by and/or affecting this legislation item
  • confers power and blanket amendment details
  • all formats of all associated documents
  • correction slips
  • links to related legislation and further information resources
Close

More Resources

Use this menu to access essential accompanying documents and information for this legislation item. Dependent on the legislation item being viewed this may include:

  • the original print PDF of the as made version that was used for the print copy
  • correction slips

Click 'View More' or select 'More Resources' tab for additional information including:

  • lists of changes made by and/or affecting this legislation item
  • confers power and blanket amendment details
  • all formats of all associated documents
  • links to related legislation and further information resources