The Private Water Supplies (Amendment) Regulations (Northern Ireland) 2015

“Requirement to carry out a risk assessment7.

(1)

The Department shall carry out an assessment (“risk assessment”) of the potential risks associated with each private supply to which these Regulations apply (other than a supply under regulation 11) and subsequently review and update that risk assessment every five years (or earlier if it considers that the existing risk assessment is inadequate).

(2)

The Department shall carry out a risk assessment, where the private supply is a new supply and is to be used for the first time, within six months of that supply being monitored under regulations 9 and 10.

(3)

The Department may enter into an arrangement for any person to carry out a risk assessment on its behalf for the purposes of this regulation.

(4)

The Department may provide for any such person to be reimbursed.

(5)

The Department shall not enter into an arrangement under paragraph (3) unless it is satisfied that the task will be carried out promptly by a person competent to perform it.”

“(7A)

The Department shall carry out a representative survey in accordance with the following to determine the likelihood of a supply failing the radon maximum concentration or value specified in Schedule 1 Part 2;

A representative survey must be designed in such a way—

(a)

as to be capable of determining the scale and nature of likely exposures to radon in water intended for human consumption originating from different types of groundwater sources and wells in different geological areas; and

(b)

that underlying parameters, especially the geology and hydrology of the area, radioactivity of rock or soil, and well type, can be identified and used to direct further action to areas of likely high exposure.”

“8.

(1)

The Department shall monitor all private supplies in accordance with this Part.

(2)

Samples required to be taken in accordance with this Part shall be taken at regular intervals so as to be representative of the quality of the water consumed throughout the year”

“PART 2Indicator Parameters

Parameters	Maximum concentration or value or state (unless otherwise stated)	Units of measurement
Ammonium	0.50	mgNH4/l
Chloride(1)	250	mgCl/l
Clostridium perfringens (including spores)	0	Number/100ml
Coliform bacteria	0	Number/100ml
Colony counts	No abnormal change No abnormal change	Number/1ml at 22oC Number/1ml at 37oC
Conductivity(1)	2,500	µS/cm at 20oC
Hydrogen ion(1)	9.5 6.5 (minimum)	pH value pH value
Sulphate(1)	250	mgSO4/l
Indicative dose (for radioactivity)(2)(3)(4)	0.10	mSv/year
Radon (for radioactivity)(3)(5)	100	Bq/1
Total organic carbon(TOC)	No abnormal change	mgC/l
Tritium (for radioactivity)(3)(6)	100	Bq/l
Turbidity(7)	1	NTU”

(1)

The water should not be aggressive.

(2)

Excluding tritium, potassium-40, radon and radon decay products.

(3)

Where treatment to reduce the level of radionuclides in water intended for human consumption has being taken, monitoring must be carried out under Schedule 3 Part 1 to ensure the continued efficacy of treatment.

(4)

If the gross alpha activity exceeds 0.1Bq/l or the gross beta activity exceeds 1.0Bq/l analysis for specific radionuclides is required.

(5)

Remedial action is deemed to be justified on radiological protection grounds, without further consideration, where radon concentrations exceed 1000Bq/l.

(6)

If tritium concentration exceeds its parametric value an investigation (which may include analysis) of the presence of other artificial radionuclides must be carried out.

(7)

Only in the case of surface water treatment where the parametric value should be strived for the water ex-treatment works.

“PART 1Check Monitoring

Sampling1.

Check monitoring means sampling for each parameter listed in Table A in the circumstances listed in that table.

Table ACheck Monitoring

Parameter	Circumstances
Aluminium	When used as flocculant or where the water originates from, or is influenced by, surface waters
Ammonium	In all supplies
Clostridium perfringens (including spores)	Where the water originates from, or is influenced by, surface waters
Coliform bacteria	In all supplies
Colour	In all supplies
Conductivity	In all supplies
Escherichia coli (E. coli)	In all supplies
Hydrogen ion	In all supplies
ID	Where treatment to reduce the level of radionuclides in water intended for human consumption has been taken
Iron	When used as flocculant or where the water originates from, or is influenced by, surface waters
Manganese	Where the water originates from, or is influenced by, surface waters
Nitrate	When chloramination is practised
Nitrite	When chloramination is practised
Odour	In all supplies
Radon	Where treatment to reduce the level of radionuclides in water intended for human consumption has been taken
Taste	In all supplies
Tritium	Where treatment to reduce the level of radionuclides in water intended for human consumption has been taken
Turbidity	In all supplies
Disinfectant residual	When disinfection treatment is practised

Frequency of sampling2.

(1)

Sampling for non-radioactive substances shall be carried out at frequencies specified in table B of this Schedule and sampling for radioactive substances shall be carried out at frequencies specified in table B1 of this Schedule.

TABLE BSampling frequency for check monitoring

Volume m3/day	Sampling frequency per year
≤10	1
> 10 ≤ 100	2
> 100 ≤ 1,000	4
> 1,000 ≤ 2,000	10
> 2,000 ≤ 3,000	13
> 3,000 ≤ 4,000	16
> 4,000 ≤ 5,000	19
> 5,000 ≤ 6,000	22
> 6,000 ≤ 7,000	25
> 7,000 ≤ 8,000	28
> 8,000 ≤ 9,000	31
> 9,000 ≤ 10,000	34
> 10,000	4 + 3 for each 1,000 m3/day of the total volume (rounding up to the nearest multiple of 1,000 m3/day)

TABLE B1

Volume m3 /day	Sampling frequency per year
≤ 1000	1
> 1000 ≤ 10,000	1 + 1 for each 3,300 m3/day of the total volume (rounding up to the nearest multiple of 3,300 m3/day)
> 10,000 ≤ 100,000	3 + 1 for each 10,000 m3/day of the total volume (rounding up to the nearest multiple of 10,000 m3/day)
> 100,000	10 + 1 for each 25,000 m3/day of the total volume (rounding up to the nearest multiple of 25,000 m3/day)

(2)

The Department may reduce the frequency of sampling for a parameter within Table B to a frequency not less than half if—

(a)

it is of the opinion that the quality of water in the supply is unlikely to deteriorate;

(b)

in the case of hydrogen ion the parameter has had a pH value that is not less than 6.5 and not more than 9.5; and

(c)

in all other cases, in each of two successive years the results of samples taken for the purposes of monitoring the parameter in question are constant and significantly lower than the concentrations or values laid down in Schedule 1.

(3)

The Department may set a higher frequency for any parameter if it considers it appropriate taking into account the findings of any risk assessment, and in addition may monitor anything else identified in the risk assessment.”

“(2A)

The Department shall communicate to the European Commission notice along with supporting evidence of the decision to exclude any radioactive parameters listed in Schedule 1 from the audit monitoring of a private water supply.”

“PART 3Monitoring for Indicative Dose and Analytical Performance Characteristics

Monitoring for Compliance with the ID6.

Screening strategy for gross alpha activity and gross beta activity 9 may be used to monitor for the parametric indicator value for indicative dose.

If the gross alpha activity is less than 0.1 Bq/l and the gross beta activity is less than 1.0 Bq/l, it may be assumed that the total indicative dose is less than 0.1 mSv and radiological investigation is not needed unless it is known from other sources of information that specific radionuclides are present in water that are liable to cause an excess of 0.1 mSv.

If the gross alpha activity exceeds 0.1Bq/l or the gross beta activity exceeds 1.0Bq/l analysis for specific radionuclides is required.

The radionuclides to be measured must be based on all relevant information about likely sources of radioactivity.

Calculation of the ID7.

The ID must be calculated from the measured radionuclide concentrations and the dose coefficients laid down in Annex III, Table A of Directive 96/29/Euratom10 or more recent information recognised by the Department, on the basis of the annual intake of water (730 l for adults).

Where the following formula is satisfied, it can be assumed that the ID is less than the parametric value of 0.1mSv and no further investigation is required.

$${\displaystyle \colorbox[rgb]{}{$\sum _{i=1}^n\genfrac{}{}{0.1ex}{}{Ci(obs)}{Ci(der)}$}}\le 1$$

where

C_i(obs) = observed concentration of radionuclide i

C_i(der) = derived concentration of radionuclide i

n = number of radionuclides detected.

Table C

Derived concentrations for radioactivity in water intended for human consumption(1)
Origin	Nuclide	Derived concentration
Natural	U-238(2)	3.0 Bq/l
	U-234(2)	2.8 Bq/l
	Ra-226	0.5 Bq/l
	Ra-228	0.2 Bq/l
	Pb-210	0.2 Bq/l
	Po-210	0.1 Bq/l
Artificial	C-14	240 Bq/l
	Sr-90	4.9 Bq/l
	Pu-239/Pu-240	0.6 Bq/l
	Am-241	0.7 Bq/l
	Co-60	40 Bq/l
	Cs-134	7.2 Bq/l
	Cs-137	11 Bq/l
	I-131	6.2 Bq/l

(1)

This table includes values for the most common natural and artificial radionuclides; these are precise values, calculated for a dose of 0.1mSV, an annual intake of 730 litre and using the dose coefficients laid down in Annex III Table A of Directive 96/29/Euratom; derived concentration for other radionuclides can be calculated on the same basis, and values can be updated on the basis of more recent information recognised by the Department.

(2)

This table allows only for the radiological properties of uranium, not for its chemical toxicity.

Performance characteristics and method of analysis.8.

For the following parameters and radionuclides, the method of analysis used must, as a minimum be capable of measuring activity concentrations with a limit of detection specified below in Table D:

Table D

Parameters and radiouclides	Limit of detection(1)(2)
Tritium	10 Bg/l(3)
Radon	10 Bg/l(3)
gross alpha activity	0.04 Bg/l(4)
gross beta activity	0.4 Bg/l(4)
U-238	0.02 Bg/l
U-234	0.02 Bg/l
Ra-226	0.04 Bg/l
Ra-228	0.02 Bg/l(5)
Pb-210	0.02 Bg/l
Po-210	0.01 Bg/l
C-14	20 Bg/l
Sr-90	0.4 Bg/l
Pu-239/Pu-240	0.04 Bg/l
Am-241	0.06 Bg/l
Co-60	0.5 Bg/l
Cs-134	0.5 Bg/l
Cs-137	0.5 Bg/l
I-131	0.5 Bg/l”

(1)

The limit of detection must be calculated according to the ISO standard 11929: Determination of the characteristic limits (decision threshold, detection limit, and limits of the confidence interval) for measurements of ionising radiation – Fundamentals and application, with probabilities of error of 1^st and 2^nd kind of 0.05 each.

(2)

Measurement uncertainties must be calculated and reported as complete standard uncertainties or as expanded standard uncertainties with an expansion factor of 1.96 according the ISO Guide for the Expression of Uncertainty in Measurement.

(3)

The limit of detection for tritium and for radon is 10% of its parametric value of 100 Bg/l.

(4)

The limit of detection for gross alpha activity and gross beta activities are 40% of the screening values of 0.1 and 1.0 Bg/l respectively.

(5)

This limit of detection applies only to initial screening for ID for a new water source, if initial checking indicates that it is not plausible that Ra-228 exceeds 20% of the derived concentration, the limit of detection may be increased to 0.08 Bg/l for routine Ra-228 nuclide specific measurements until a subsequent re-check is required.