Sample reportsEL-2026-04817 · Sample report

Tap water · Westminster Jug filter · Performance

Independent water analysis · London

EL-2026-04817

Drinking water analysis report

Full Drinking Water Analysis — Westminster, London

A complete as-supplied analysis of mains drinking water from a central London property, covering every parameter group in our testing catalogue.

Report number: EL-2026-04817
Date sampled: 29 July 2026, 08:15
Date received: 29 July 2026, 14:40
Date issued: 12 August 2026
Sample point: Kitchen cold tap, first-floor flat
Location: Westminster, London SW1
Supply zone: Central London (surface-water derived)
Sample type: Mains drinking water, as supplied
Sampling protocol: Flushed and first-draw pair, 5 L composite
Temperature on receipt: 4.8 °C

Summary

The sample met every statutory and guideline reference value applied in this report. Hardness is high, chlorination by-products and trace PFAS were measurable but well below guideline values.

Sixty-eight individual determinations were carried out across PFAS, metals, microbiology, inorganic chemistry, volatile organics, pesticides, microplastics and physical properties. No result exceeded a UK statutory limit or the guideline values applied in this report. Microbiological indicators were absent. Trace PFAS were quantified at single-digit nanograms per litre, roughly an order of magnitude below the 100 ng/L guideline applied to the sum of twenty compounds. Total trihalomethanes were measured at approximately one third of the 100 µg/L limit, consistent with a chlorinated surface-derived supply. The most practically significant finding is hardness at 278 mg/L as CaCO₃, which is classified as hard and has no health-based limit.

68 determinations; no result above an applied statutory or guideline value
E. coli, coliforms and enterococci all absent in 100 mL
PFAS sum of 20 compounds: 10.5 ng/L against a 100 ng/L guideline
Total THMs 31 µg/L against a 100 µg/L limit
Lead 1.9 µg/L against a 10 µg/L limit — plumbing-derived, first-draw dependent
Hardness 278 mg/L CaCO₃ (hard); microplastics detected at 1.4 particles/L

Determinations

Individual parameters reported

Exceedances

Against applied reference values

PFAS sum

10.5

ng/L of a 100 ng/L guideline

Hardness

278

mg/L CaCO₃ — classified hard

Full Drinking Water Analysis — Westminster, London · Issued 12 August 2026Page 1 of 5

Independent water analysis · London

EL-2026-04817

Results

Results are reported as received, with the limit of detection and the reference value applied to each parameter.

PFAS

7 parameters

Determined by LC-MS/MS with isotopically labelled internal standards.

Parameter	Unit	Result	LOD	Reference	Method
PFOA	ng/L	3.1	0.5	Guideline 100 (individual)	LC-MS/MS
PFOS	ng/L	2.4	0.5	Guideline 100 (individual)	LC-MS/MS
PFHxS	ng/L	1.2	0.5	—	LC-MS/MS
PFBS	ng/L	1.8	0.5	—	LC-MS/MS
PFNA	ng/L	< 0.5	0.5	—	LC-MS/MS
PFHxA	ng/L	2.0	0.5	—	LC-MS/MS
PFAS — sum of 20 compounds	ng/L	10.5	—	Guideline 100 (sum)	LC-MS/MS

Metals and trace elements

11 parameters

Parameter	Unit	Result	LOD	Reference	Method
Lead	µg/L	1.9	0.5	10	ICP-MS
Copper	mg/L	0.081	0.005	2.0	ICP-MS
Nickel	µg/L	2.6	0.5	20	ICP-MS
Iron	µg/L	14	5	200	ICP-MS
Manganese	µg/L	2.1	1	50	ICP-MS
Arsenic	µg/L	0.7	0.5	10	ICP-MS
Chromium	µg/L	0.6	0.5	50	ICP-MS
Cadmium	µg/L	< 0.1	0.1	5	ICP-MS
Mercury	µg/L	< 0.05	0.05	1	ICP-MS (CV)
Aluminium	µg/L	31	5	200	ICP-MS
Sodium	mg/L	38	1	200	ICP-OES

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Independent water analysis · London

EL-2026-04817

Microbiology

4 parameters

Analysed within 12 hours of receipt.

Parameter	Unit	Result	LOD	Reference	Method
E. coli	cfu/100 mL	0	1	0	Membrane filtration
Total coliforms	cfu/100 mL	0	1	0	Membrane filtration
Enterococci	cfu/100 mL	0	1	0	Membrane filtration
Colony count, 22 °C	cfu/mL	4	1	No abnormal change	Plate count

Inorganic chemistry

7 parameters

Parameter	Unit	Result	LOD	Reference	Method
Nitrate	mg/L NO₃	24.6	0.5	50	Ion chromatography
Nitrite	mg/L NO₂	< 0.02	0.02	0.5	Ion chromatography
Fluoride	mg/L	0.19	0.05	1.5	Ion chromatography
Free chlorine	mg/L	0.38	0.02	Operational	Colorimetry (DPD)
Total chlorine	mg/L	0.51	0.02	Operational	Colorimetry (DPD)
Sulphate	mg/L	62	1	250	Ion chromatography
Chloride	mg/L	48	1	250	Ion chromatography

Volatile organics and pesticides

5 parameters

Parameter	Unit	Result	LOD	Reference	Method
Total trihalomethanes (THMs)	µg/L	31	1	100	GC-MS (headspace)
Chloroform	µg/L	24	1	—	GC-MS (headspace)
Bromodichloromethane	µg/L	5.4	1	—	GC-MS (headspace)
VOCs — 32 compound screen	µg/L	All < LOD	0.5	—	GC-MS (headspace)
Pesticides — 60 compound screen	µg/L	Metaldehyde 0.041	0.01	0.1 (individual)	LC-MS/MS

Full Drinking Water Analysis — Westminster, London · Issued 12 August 2026Page 3 of 5

Independent water analysis · London

EL-2026-04817

Microplastics

2 parameters

Reported as particles per litre in the 20 – 500 µm size range.

Parameter	Unit	Result	LOD	Reference	Method
Microplastic particles, 20 – 500 µm	particles/L	1.4	0.5	No statutory limit	µ-FTIR after filtration
Dominant polymer identified	—	Polyethylene terephthalate	—	—	µ-FTIR

Physical properties

6 parameters

Parameter	Unit	Result	LOD	Reference	Method
pH	pH units	7.6	—	6.5 – 9.5	Electrometric
Total hardness	mg/L CaCO₃	278	5	Hard (no health limit)	ICP-OES (Ca, Mg)
Hardness (Clark degrees)	°Clark	19.5	—	Hard	Calculated
Turbidity	NTU	0.21	0.05	4	Nephelometric
Conductivity, 20 °C	µS/cm	684	1	2500	Electrometric
Total organic carbon	mg/L	1.6	0.2	—	Combustion / NDIR

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Independent water analysis · London

EL-2026-04817

Technical observations

01
Lead, copper and nickel in drinking water usually originate from the property's own plumbing rather than the supply. First-draw and flushed results were consistent in this sample, indicating no significant plumbing contribution.
02
Trihalomethanes form when chlorine reacts with natural organic matter. Concentrations vary through the year and with distance from the treatment works.
03
Hardness at 278 mg/L CaCO₃ affects scale formation and taste, not compliance. There is no health-based limit for hardness in UK drinking water.
04
A non-detect result means the parameter was not measured above the stated limit of detection for that method. It does not mean the parameter is absent at every concentration.

Reading this report

Detection limits

Every parameter is reported with its limit of detection. A result below that limit is reported as “< LOD” and means the parameter was not measured above it.

Reference values

Where a UK statutory limit or recognised guideline exists it is shown alongside the result. Parameters without a health-based limit are marked informational.

Scope

Results relate solely to the sample as received and to the parameters listed. They are not a statement about the wider supply or about other units of the same product.

Authorised by

Technical Manager, London Water Testing

Testing & analysis

Testing managed by London Water Testing, London. Analysis performed by accredited specialist partner laboratories; the analysing laboratory and its accreditation status are stated on the issued report and are intentionally omitted from this illustrative sample.

Illustrative sample report

Values are modelled on published water-quality information for the Westminster supply zone and on typical performance ranges for domestic filters. This document demonstrates report layout and reporting conventions and is not the analysis of any specific property or product.

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