When something goes wrong with the water, the instinct is to boil it. Boiling has been the default response to water quality concerns for generations, and for good reason: it works against the threats that historically made water dangerous.
The problem is that the threats that historically made water dangerous — bacteria, viruses, parasites — are not the primary threats in 21st-century Connecticut. The threats that matter most in Connecticut today are chemical: lead, PFAS, nitrates, arsenic, disinfection byproducts. And for chemical contamination, boiling doesn't help. For some chemicals, it makes things worse.
What Boiling Actually Does
Boiling water to a rolling boil for one minute kills:
- Bacteria, including E. coli, Salmonella, and Campylobacter
- Viruses, including norovirus and hepatitis A
- Parasites, including Giardia and Cryptosporidium
This is genuinely valuable. When a Connecticut town issues a boil water notice — typically after a water main break, a treatment system failure, or a flooding event that may have introduced biological contamination — boiling is the correct response to the specific risk the notice addresses. The CDC recommends a rolling boil for one minute as the standard protocol.
What Doesn't Boiling Remove from Water?
Boiling does not remove:
- Lead: Lead is a dissolved metal. It doesn't evaporate when water boils. It stays in the water. Worse, as water boils away as steam, the remaining water becomes more concentrated — the same amount of lead in less water means higher lead concentration.
- PFAS: PFAS compounds don't evaporate at boiling temperatures. They stay in the water, and as water volume decreases through boiling, their concentration increases.
- Nitrates: Nitrates are dissolved salts. They don't evaporate. Boiling concentrates them.
- Arsenic: Same as lead — a dissolved metal that concentrates as water boils away.
- Chlorine byproducts: Trihalomethanes (THMs) are volatile and do partially evaporate during boiling. However, haloacetic acids (HAAs) do not evaporate and may concentrate.
The Yale School of the Environment study published in February 2026 made this point explicitly: researchers found that while boiling was the recommended response to biological contamination, "boiling does not remove metals — and can sometimes concentrate them."
The Connecticut Context
Connecticut's most common water quality concerns are chemical, not biological. Lead in service lines and old solder. PFAS in groundwater-dependent supplies. Nitrates in agricultural well water. Arsenic in granite bedrock geology.
For all of these, boiling is not just ineffective — it's potentially counterproductive. A Connecticut homeowner who is worried about lead in their water and responds by boiling it is concentrating the lead they're trying to avoid.
The right response to chemical contamination is filtration. For lead: an NSF/ANSI 53 certified filter. For PFAS: an NSF/ANSI 58 certified reverse osmosis system or an NSF P473 certified filter. For nitrates: reverse osmosis. For arsenic: reverse osmosis or activated alumina. For a deeper look at what reverse osmosis actually removes, see our complete breakdown of RO filtration.
Boil water notices are issued for biological contamination. They are not a general water quality intervention. If you're boiling your water because you're worried about what's in it — and you haven't identified the specific contaminant you're concerned about — the first step is to test, not to boil. Your annual water quality report is a good starting point — here's how to actually read it.
Ready to check your own water? Enter your ZIP code at CheckYourTap.com to see what's in your tap water — free, in 30 seconds.
Keep Reading
- Reverse Osmosis Removes Almost Everything. Here's What Connecticut Homeowners Need to Know Before Buying One.
- Your Water Quality Report Arrived. Here's How to Actually Read It.
- A Practical Guide to Water Quality in Connecticut's Major Towns — What's Actually in the Water Where You Live
Frequently Asked Questions
Does boiling water remove lead?
No. Lead is a dissolved metal that does not evaporate at boiling temperatures. Boiling actually concentrates lead by reducing the water volume — the same amount of lead in less water means a higher concentration per glass.
What contaminants does boiling water remove?
Boiling kills biological contaminants including bacteria (E. coli, Salmonella), viruses (norovirus, hepatitis A), and parasites (Giardia, Cryptosporidium). It does not remove chemical contaminants like lead, PFAS, nitrates, arsenic, or most disinfection byproducts.
What should I do instead of boiling water for chemical contamination?
Use certified filtration. For lead, use an NSF/ANSI 53 certified filter. For PFAS, use an NSF/ANSI 58 reverse osmosis system or NSF P473 certified filter. For nitrates and arsenic, reverse osmosis is the most effective option.
Sources: Yale School of the Environment / Water journal, February 2026; EPA Boil Water Notice Guidance; CDC Safe Water Guidance; NSF International Filter Certification Standards; EPA Drinking Water Contaminant List.