Most people choose a water filter based on taste. But the research points to a different set of contaminants — microplastics, PFAS forever chemicals, and heavy metals — that most common filters don’t address. This evidence-based water filtration guide covers what each filter type removes, what it doesn’t, and which one the research supports.

The Short Version

  • RO removes >99% of microplastics from drinking water — no other common home filter comes close
  • Standard pitcher filters (Brita, PUR) do not remove microplastics — they’re built for taste and chlorine, not particles
  • PFAS “forever chemicals” have been detected in water supplies across the US and Europe, with near-zero safe exposure levels per the EPA
  • Bottled water is not the solution — 93% of bottled water brands tested in a 2018 global study contained microplastics, often at higher concentrations than tap water
  • A countertop RO system addresses the highest-volume daily exposure route and requires no plumbing or installation

What Your Filter Is Actually Up Against

Your tap water may contain three categories of contaminants that standard filters don’t handle well.

Microplastics

Microplastics have been found in human blood and organs — including lungs, heart tissue, and placenta. A 2018 global study found them in 81% of tap water samples worldwide. They enter the water supply through plastic degradation, industrial runoff, and plastic distribution pipes. At 1 micron and up, they pass straight through most carbon filters.

PFAS (Forever Chemicals)

Per- and polyfluoroalkyl substances (PFAS) are synthetic compounds used in nonstick cookware, waterproof clothing, and food packaging. They don’t break down in the environment or in the human body. The EPA lowered its health advisory for two major PFAS compounds to near zero in 2022, reflecting growing evidence of harm at extremely low concentrations. PFAS has been detected in public water supplies serving hundreds of millions of people.

Heavy Metals

Lead, arsenic, and cadmium can enter drinking water from aging pipes, industrial runoff, and agricultural use. Lead is particularly common in older homes and cities with aging infrastructure. Unlike microplastics, heavy metals are dissolved — not filtered by physical pore size alone.

Filter Types Compared

Not all filters address all three threat categories. Here’s an honest look at what each technology does and doesn’t do.

Pitcher filters (Brita, PUR): Activated carbon removes chlorine, improves taste, and reduces some heavy metals like lead and cadmium. Does not remove microplastics. Provides partial PFAS reduction but not reliably complete removal. Cost: ~$30 plus replacement cartridges.

Countertop RO (AquaTru): Four-stage reverse osmosis removes >99% of microplastics, >95% of most PFAS compounds, and heavy metals including lead, arsenic, and chromium-6. Independently certified to NSF standards 42, 53, 58, 401, and P473. No plumbing required. Cost: ~$400 plus ~$85/year in filters.

Under-sink RO (Waterdrop G3P800): Same RO performance as the AquaTru countertop, with higher flow rate and no counter footprint. Requires installation — a hole in the counter for the dedicated faucet and a cold-water line connection. Better for homeowners with higher daily volume needs. Cost: ~$500–700 plus ~$150/year in filters.

Whole-house filtration: Protects all water uses in the home — drinking, cooking, bathing, and laundry. Addresses pipe contamination at the point of entry. Highest upfront cost ($500–$3,000+) and typically requires professional installation. Most practical where PFAS or heavy metal contamination is a documented local problem.

For a detailed side-by-side including specific product picks at each price point, see our detailed water filter comparison.

The Reduction Roadmap

You don’t need to solve everything at once. These three steps address the most exposure with the least friction.

  1. Filter your drinking water with an RO system. This is the single highest-impact change for most households. RO removes microplastics, PFAS, and heavy metals in one step. For renters, a countertop unit requires no plumbing. For homeowners, under-sink is more cost-effective per gallon over time.

  2. Switch to glass or stainless steel bottles. Plastic bottles shed microplastics into the water they hold — more so as the bottle ages and accumulates scratches. Glass and stainless steel sidestep this entirely and are compatible with filtered tap water.

  3. Use filtered water for cooking and ice. Boiling water concentrates dissolved contaminants. Ice cubes made from unfiltered tap water are another daily source. Running your cooking and ice through the same filter as your drinking water extends the benefit without extra cost.

Go Deeper

These posts cover the research behind each claim in this guide:

This article is for informational purposes only and does not constitute medical advice.

Frequently Asked Questions

Does a Brita filter remove PFAS?
Standard Brita pitcher filters use activated carbon, which reduces some PFAS compounds but not reliably or completely. Reverse osmosis systems are the most effective option, removing >95% of PFAS compounds.
What is the best water filter for microplastics?
Reverse osmosis is the most effective technology — RO membranes block particles down to 0.0001 microns, smaller than any microplastic. See our full comparison for countertop vs under-sink options at different price points.
Is bottled water safer than tap water?
No. A 2018 study found microplastics in 93% of bottled water brands tested, often at higher concentrations than tap water. RO-filtered tap water is a cleaner and cheaper option.
How do I know if my tap water has PFAS?
The EPA’s PFAS map and your local water utility’s annual water quality report (Consumer Confidence Report) will tell you what’s been detected. You can also use a certified lab test kit — search for NSF-certified PFAS testing.