Are there microplastics in UK tap and bottled water?

Part of our tap water guide

The headlines say we are drinking plastic. What have the studies measured, and what does that tell you about your own tap, which you can check on other measures with a 20-in-1 test strip?

By Andrew Tomlinson, WaterKit · Last reviewed 29 October 2026

Are there microplastics in tap and bottled water?

Yes, researchers have found them in both, but the counts depend heavily on the method used. The World Health Organization (WHO) information sheet says only 9 studies had measured microplastics in drinking water. A strip cannot count particles, but you can see how your own tap reads on other measures with a 20-in-1 test strip, as we explain at the end.

WHO says a study it commissioned judged most of the studies not fully reliable, because their methods lacked quality control. In two drinking-water studies, and part of a third, nobody ran a spectroscopic check that the particles were plastic. WHO also says there is no agreed scientific definition of microplastics, though they are often defined as plastic particles under 5 mm.

Is there more microplastic in bottled water than in tap water?

In the studies WHO reviewed, bottled water had higher counts, but WHO says that is too thin to conclude from. At the launch briefing on 20 August 2019, a WHO scientist said both bottled and tap water showed very large ranges and she did not want to make sweeping conclusions. The studies were few and the methods differed.

The same briefing said the two plastics most often detected were polyethylene terephthalate, used for bottles, and polypropylene, used for caps. WHO's information sheet says bottles and caps may be a source, and the briefing mentioned suspicion about caps and the packaging process. In the sources we read, none gave a UK survey of bottled water. Our tap versus bottled water guide covers the wider comparison.

What do health bodies say about the risk?

WHO's assessment is that the risk is low, on limited evidence. Its 2019 report and information sheet say this, and at the launch briefing WHO's Bruce Gordon added that it could not "rule out conclusively that there might never be a risk in the future".

• Chemicals and biofilms linked to microplastics in drinking water are a low concern.
• There is not enough information for firm conclusions on the particles themselves, though no reliable information suggests a concern.
• Particles over 150 micrometres are likely to pass through the gut, and there are no human studies on ingested microplastics.
• Routine monitoring of microplastics in drinking water is not necessary at this time.

The DWI-published research reached a similar view, concluding that the risk of adverse effects from environmental exposure is small, while noting that data on nanoplastics are lacking. It says only particles under 150 micrometres are taken up in the gut (no more than about 0.3% of the exposed dose), and that only those under 20 micrometres are thought to reach other organs. A later WHO report widened the review to food, water and air, using data up to December 2021. We found no UK limit for microplastics in the sources we read.

WHO also says microbial pathogens remain the most significant drinking-water threat, and that suppliers should keep prioritising those.

Does water treatment remove microplastics?

In trials, yes. The DWI-published work tested four common plastics (polyethylene, polypropylene, polystyrene and polyethylene terephthalate) in three shapes, 20 to 150 micrometres across. In jar tests, coagulation separated 96% of a starting load of about 1,000 particles per litre. In the pilot plant, filtration retained the small numbers that escaped coagulation. Spheres and fibres were removed better than irregular fragments.

WHO says wastewater treatment can remove more than 90% of microplastics, and that advanced treatment such as nanofiltration and ultrafiltration removes even smaller particles. The DWI-published removal figures come from lab and pilot trials on particles of 20 to 150 micrometres, so they do not describe any one works or tap.

Why might your tap differ from the studies?

The sources we read give no area figure for microplastics, only ranges and averages from a handful of studies. A figure for the area does not tell you what comes out of your own tap. WHO's own numbers show the spread, with single drinking-water samples from 0 to 10,000 particles per litre, so one sample cannot stand for a whole area.

A WHO co-author said at the 2019 briefing that it was still unclear whether particles come from the source water or arrive through the supply chain, from treatment or distribution. In the DWI research pages we read, we found no company or local microplastics figure, and its last aim was to propose monitoring "a small number of final waters", which is a sample rather than your tap.

“I wouldn't treat an area figure, or a single study result, as a description of what comes out of your own tap. Your supply chain and your pipes are specific to you, so it's sensible to check what you can at home rather than assume the average applies.”

What you can check at home is how your tap and your filtered or bottled water compare on pads the 20-in-1 strip does read. That is separate from particles.

Do water filters remove microplastics?

In the sources we read, none tested home filter jugs. WHO's Bruce Gordon said at the 2019 briefing that filters and treatment options in many countries can remove microplastics from drinking water, without naming types. At the works, WHO describes nanofiltration (particles above 0.001 micrometres) and ultrafiltration (above 0.01 micrometres). Our filter jug guide, tap water filtering guide and reverse osmosis guide cover home filters more widely.

Can you test for microplastics at home, and what can a strip show?

Not that we found. WHO says quality control in these studies needed polymer identification, clean-air conditions and laboratory preparation. The DWI-published research says there is no harmonised method for identifying and quantifying microplastics in foods and biological specimens, and one detection method has a 20 micrometre threshold.

The WaterKit strip does not test for microplastics, plastic particles or the chemicals in plastics. The strip gives readings for chlorine, hardness, pH, nitrate and copper, among others, in 30 to 60 seconds. Dip a strip in a clean glass of tap water, then another in your filtered or bottled water, and compare the pads. On our reading of the chart, a lower free chlorine colour in the filtered glass (pad steps 0, 0.5, 1, 3, 5, 10 and 20 mg/l) indicates the filter changed the chlorine level, and a different reading on any pad indicates the water differs on that pad and says nothing about particles. Our water testing guide has the steps, and you can enter colours in the results portal.

• The strip cannot read lead at the UK limit. See our lead pipes guide instead.
• The nitrite, iron, mercury, chromium, aluminium and fluoride pads first change colour above UK limits, so a clear result is not a pass.
• The optional bacteria test is a presence screen for coliforms, read after 24 to 48 hours. We do not claim the test for bottled water. A strip result has no legal effect.

Best pack: 20 strips, enough to test your tap, then filtered and bottled water side by side, and repeat after a cartridge change, £5.99 (or £10.99 with a bacteria test), with free 2nd Class delivery on every order. See the kit

Your microplastics questions

Does bottled water contain microplastics?

Studies have found them, and WHO's reviewers saw higher counts in bottled water, with the cautions above.

How much microplastics are in bottled water?

WHO's review gives no single figure we could use. Its drinking-water range of 0 to 10,000 particles per litre covers tap and bottled samples, and WHO said bottled water also showed very large ranges.

Do water filter jugs remove microplastics? Do water filter pitchers have microplastics?

In the sources we read, none tested jugs, so we cannot say.

Can you filter microplastics out of bottled water?

The sources we read do not cover filtering bottled water at home.

How to filter microplastics from water?

Water works use coagulation and filtration, and WHO names nanofiltration and ultrafiltration for the smallest particles.

How to test microplastics in water? How to test for plastic in water?

Only in a laboratory, as far as we found.

Sources

1. World Health Organization, Microplastics in drinking-water (2019 report, publication page; undated page; read 29 October 2026), its information sheet (key messages, study counts, treatment removal and recommendations; read 29 October 2026) and the launch briefing transcript (20 August 2019; bottled versus tap, filter size caution, polymers; read 29 October 2026).
2. World Health Organization, Dietary and inhalation exposure to nano- and microplastic particles and potential implications for human health (publication page; data published up to December 2021; read 29 October 2026).
3. Drinking Water Inspectorate, Research on Removal of Microplastics by Drinking Water Treatment Processes (DWI 70/2/326, published 11 October 2022; read 29 October 2026) and its executive summary (surface water ranges, uptake sizes, jar tests; read 29 October 2026).
4. WaterKit, Water Test Kit (20-in-1 strip, 30 to 60 second read, optional bacteria test read after 24 to 48 hours, 20 strips £5.99 or £10.99 with a bacteria test, free 2nd Class delivery on every order) and results portal. The comments on what the pads indicate are WaterKit's own reading of the colour chart.

Contains public sector information licensed under the Open Government Licence v3.0.