What to Watch in 2026: PFAS, Microplastics & The Changing Science of Drinking Water

Across Australia and globally, water quality science is evolving rapidly. Emerging contaminants, improved monitoring methods, and shifting regulatory benchmarks are reshaping how experts think about drinking water safety.

The latest HealthStream – Water Quality Issue 116 (Dec 2025) highlights several developments that matter not only to water professionals — but increasingly to informed households.

Here's what to watch in 2026.

1. PFAS: The Ubiquitous 'Forever Chemicals'

Per- and polyfluoroalkyl substances (PFAS) continue to dominate global water discussions.

According to a 2025 assessment of Sydney drinking water summarised in HealthStream:

• At least one PFAS compound was detected in all tap and bottled water samples tested.
• None exceeded the updated Australian Drinking Water Guidelines (ADWG) values.
• One location near an air force base recorded PFOS slightly above the new U.S. EPA benchmark (4 ng/L), but below Australian guideline values.

The takeaway?

PFAS are widespread at very low levels. The regulatory conversation is shifting from "Are they present?" to:

• How should mixtures be assessed?
• How often should guideline values be reviewed?
• What level of precaution is appropriate?

The NSW Parliamentary Inquiry into PFAS (Sept 2025), also summarised in HealthStream, recommended:

2. Mixture Risk: The Next Scientific Frontier

One emerging challenge is mixture risk assessment.

Thousands of PFAS compounds exist, and many occur together. A 2025 expert workshop summarised in HealthStream recommended grouping similar PFAS and assessing cumulative effects.

However, the framework remains conceptual.

In practical terms:

Science is still refining how to evaluate low-level, long-term exposure to multiple trace contaminants.

Expect 2026 to bring:

• Updated guideline reviews
• International benchmark comparisons
• Continued refinement of health-based targets

3. Effects-Based Monitoring: Looking Beyond What We Test For

Traditional water testing looks for known chemicals.

But 2025 research reviewed in HealthStream shows that effect-based monitoring (EBM) — bioassays that measure biological activity — can detect impacts that chemical screening alone misses.

Key findings from Australian and European studies:

• Wastewater treatment significantly reduces contaminants.
• However, some biological activity persists downstream.
• Not all observed biological effects can be explained by chemicals routinely tested.

This doesn't mean water is unsafe.

It means science is expanding beyond "what we can measure chemically" to "what biological systems respond to.

That shift is likely to influence future water filtration technology and regulatory thinking.

4. Disinfection Byproducts & Oxidation Advances

Climate change and nutrient enrichment are driving more frequent cyanobacterial blooms in source waters.

The lead article in Issue 116 explores ozone nanobubble technology as a next-generation oxidation tool to manage:

• Cyanobacteria
• Taste and odour compounds
• PFAS (when paired with granular activated carbon)
• Antibiotic resistance genes

Pilot trials showed:

• 19–34% greater oxidative efficiency than conventional ozone
• Up to 90% cyanobacterial reduction
• 15–20% improved PFAS capture when paired with GAC

For 2026, this signals:

Utilities are investing in advanced oxidation systems to improve resilience — particularly where conventional treatment faces new challenges.

5. Selenium: Quietly Revised Guidelines

In June 2025, the Australian Drinking Water Guidelines reduced the selenium health-based value from 10 µg/L to 4 µg/L.

HealthStream summarised two recent toxicological reviews supporting tighter limits, particularly noting that inorganic selenium (commonly found in water) may present higher toxicity risk than organic forms found in food.

Selenium rarely exceeds guideline levels in Australia, but the revision demonstrates:

Guidelines are dynamic. They evolve with science.

6. Aerosol Exposure: The Shower Factor

One of the more practical studies reviewed in Issue 116 examined aerosol inhalation during showering.

Key findings:

• Warmer showers (≈41°C) generate more and larger aerosols than cooler showers (≈27°C).
• Small aerosols (1–10 µm) can carry microorganisms such as Legionella.
• Exposure peaks during the first few minutes of shower operation.

Researchers suggested practical risk minimisation strategies such as:

• Avoiding the first flush of shower water
• Using cooler temperatures where possible
• Exiting promptly after showering

This reinforces that exposure pathways are not limited to drinking — inhalation also matters in water risk assessment.

7. Microplastics: The Ongoing Research Question

While microplastics were not the primary focus of Issue 116, the broader theme of emerging contaminants and advanced monitoring reflects a global push to better understand their prevalence and potential health impacts.

Expect 2026 to bring:

• Improved detection methods
• Better standardisation of measurement
• Increased public reporting transparency

The Bigger Trend: Transparency & Trust

The unifying message across Issue 116 is not alarm.

It's vigilance.

• Surveillance systems are becoming more sensitive.
• Outbreak detection is improving.
• Regulatory reviews are more frequent.
• Advanced oxidation and monitoring technologies are expanding.

Australia's drinking water system remains robust by global standards.

But the conversation is shifting from compliance alone to:

• Mixture awareness
• Emerging contaminants
• Biological effect monitoring
• Transparent reporting

What This Means for Households in 2026

For most Australians:

Tap water continues to meet national health guidelines.

However, informed households are increasingly asking:

• What is present at trace levels?
• How are mixtures assessed?
• Are guideline values changing?
• What control do I want at my own tap?

A professionally selected water filtration system, whether an under sink water filter for drinking water or a whole house water filter, is not about rejecting public infrastructure.

It is about adding a layer of personal control within the home.

Final Word: Watch the Science, Not the Headlines?

2026 will not be defined by crisis.

It will be defined by:

• Refinement of PFAS guidance
• Advances in oxidation and monitoring
• Greater public transparency

The water sector is evolving.

The more informed you are, the more empowered your decisions become.