What's in my water
Microplastics in drinking water — an honest account of what is known
Microplastics are plastic particles smaller than 5 mm, present in surface water, groundwater and treated drinking water worldwide, and currently without a regulatory limit in India or a WHO guideline value.
Limits and standards
BIS publishes two figures for many parameters: an acceptable limit, and a permissible limit that applies only where no alternate source of water exists. The second is a fallback for communities without a choice — not a target to design a purchase around.
| Standard | Limit | What it means |
|---|---|---|
| BIS IS 10500:2012 | Not a listed parameter | — |
| WHO | No guideline value | WHO's 2019 report Microplastics in Drinking-water reviewed the evidence and did not set a guideline value, recommending further research and continued focus on removing microbial and chemical contaminants of established concern. |
Where it comes from
Fragmentation of larger plastic waste
The dominant source. Plastic in the environment breaks down mechanically and by UV exposure into progressively smaller particles.
Synthetic textile fibres
Released during washing and reaching water bodies through wastewater.
Tyre and road wear particles
Carried into surface water by runoff — a large contributor in urban catchments.
Plastic pipework and storage
A plausible contributor within distribution and storage, though poorly quantified in the literature.
Bottled water
Several studies have found higher particle counts in bottled than in tap water, associated with the bottle and cap material.
Why it matters
- WHO's assessment considered particles above 150 µm unlikely to be absorbed by the human body, with limited absorption expected for smaller fractions — while noting the data on the smallest particles are sparse.
- The honest position is that this is an area of active research where confident claims in either direction are unsupported.
- It matters commercially because 'removes microplastics' has become a marketing claim in India without a test method behind it. A claim that cannot be measured cannot be verified.
Note
Can you detect it yourself?
This is the section most purifier buying decisions skip. A handheld TDS meter is the instrument almost every Indian household is shown, and for most contaminants that matter it reads exactly the same whether the contaminant is present or not.
| Question | Answer |
|---|---|
| Can you sense it? | None at the sizes discussed. |
| Does a TDS meter show it? | Nothing. Microplastics are suspended particles, not dissolved solids, and do not affect conductivity. |
| Field / home test | No consumer test exists. Any product claiming to let you test for microplastics at home is not measuring what it says it is. |
| Laboratory test to ask for | Microplastic characterisation by µ-FTIR or Raman spectroscopy — Research laboratories only; no standardised drinking-water method is in general use, which is itself the core problem (indicative ₹15,000–₹60,000) |
When to pay for a laboratory test
- None that we can honestly recommend. There is no accessible, standardised test, and no action threshold to compare a result against. Spending ₹20,000 on a research-grade analysis you cannot act on is not a good use of money.
What removes it
Effectiveness ratings below describe the technology working correctly, within its service life, on water or air that suits it. “Depends” means there is a condition in the caveat that decides the outcome — read it before buying.
- Reverse osmosis (RO)Effective
RO membrane pore size is far below any microplastic dimension, so exclusion by size is essentially complete for the microplastic range and extends well into the nanoplastic range.
Caveat: This is a physics argument from pore size, not a verified performance claim — there is no certification for microplastic reduction to point at.
- Ultrafiltration (UF)Effective
At 0.01–0.1 µm, UF excludes the entire conventional microplastic size range.
Caveat: The nanoplastic fraction below 0.1 µm is where UF's exclusion becomes partial.
- Sediment / carbon block filtrationPartial
A 1 µm absolute-rated carbon block removes larger microplastic particles. Nominal-rated filters are far less reliable.
Caveat: '1 micron' on a cartridge is often a nominal rating meaning most particles, not an absolute one meaning all.
- Conventional municipal treatmentPartial
Coagulation, sedimentation and filtration remove a substantial share of microplastics as a side effect of removing turbidity.
What does not work
Each of these is commonly assumed — or actively marketed — to help with microplastics. None of them do.
UV
Inactivates organisms; does nothing to inert particles.
Boiling
Does not remove plastic particles. Some recent work suggests boiling hard water may cause some particles to be trapped in precipitating scale, which is interesting and not a treatment recommendation.
Ion exchange softening
Targets dissolved hardness ions, not suspended particles.
Why we will not give you a removal percentage
Several purifiers sold in India carry a microplastic removal claim with a specific figure attached. There is no accepted standardised method for measuring microplastics in drinking water, which means there is no accepted method for verifying such a claim either.
What can be said with confidence is a size argument. An RO membrane rejects particles far smaller than any microplastic, and a UF membrane at 0.01 µm excludes the entire conventional microplastic range. Those statements follow from pore size and are reliable.
What cannot be said is '99.9% of microplastics removed', because nobody can measure the input or the output to a standard that would make the number mean anything. We would rather tell you the mechanism and let you draw the conclusion than repeat a figure with nothing behind it.
Note
Where this sits against contaminants we do have evidence on
WHO's report made a point that deserves repeating: focusing on microplastics should not divert attention or resources from the contaminants with established health effects and established limits.
In India that ordering is stark. Arsenic, fluoride, nitrate and bacterial contamination all have documented health consequences, known distributions, accessible tests and effective treatments. Microplastics have none of those things yet.
So the practical priority for a household is unchanged: test for the things you can act on, treat what the test finds, and treat microplastics as a reason not to switch to bottled water rather than a reason to buy something new.
Frequently asked questions
Does RO remove microplastics?
Are microplastics in drinking water dangerous?
Is there a limit for microplastics in Indian drinking water?
Does bottled water have more microplastics than tap water?
Sources
Every limit and standard quoted on this page comes from one of the documents below. Where a figure is not in one of these, we have not published it.
Guidelines for Drinking-water Quality, 4th edition incorporating the 1st addendum
World Health Organization · published 2017-04-01 · checked 2026-08-01
Microplastics in Drinking-water
World Health Organization · published 2019-08-22 · checked 2026-08-01
The primary WHO assessment. Concluded that health risk appears low on available evidence while identifying substantial gaps, including the absence of standardised measurement methods.
Bureau of Indian Standards · published 2012-05-01 · checked 2026-08-01
BIS states two figures for many parameters: an 'acceptable limit' and a 'permissible limit in the absence of an alternate source'. The second is a fallback for communities with no other supply, not a target.
This page states what published standards say and what the physics of each technology allows. It does not state what is in your supply — no page can. Where the two questions meet is a test result, and every entry in this library says which test to ask for.