Is Tap Water Safe? What the Research Says and What You Can Do About It
This was one of the most common questions put to Dr Shanna Swan by the Huberman Lab audience on X. And it is a reasonable one to ask, since water is the one thing most of us consume multiple times every single day without thinking about it.
The short answer is that UK tap water meets legal safety standards and will not make you immediately unwell. But legal safety and genuinely clean are not the same thing, and the gap between the two is worth understanding.
What Is Actually in Tap Water
UK tap water is treated to remove bacteria and pathogens, which it does effectively. The issues that concern researchers are not about acute contamination but about low level chronic exposure to compounds that the treatment process was never designed to remove, because most of them did not exist when water treatment infrastructure was built.
The main categories of concern are PFAS, pesticide residues, chlorine byproducts and microplastics. Each behaves differently in the body and responds differently to filtration.
PFAS in UK Water Supplies
The UK Government's February 2026 PFAS Plan found PFAS contamination in 88% of surface water samples and 46% of groundwater samples tested across England. Every fish sample tested contained detectable levels of PFAS.
PFAS enter water supplies from multiple sources including industrial sites, landfill leachate, firefighting foam used at airports and military bases, and agricultural runoff from fields treated with PFAS containing pesticides or fertilisers. Standard water treatment removes some PFAS but not all, and the newer short chain PFAS compounds that many manufacturers switched to after older ones were regulated are particularly difficult to remove.
The UK currently has no specific legal limit for total PFAS in drinking water, though this is under review following the February 2026 PFAS Plan. By contrast, the US EPA adopted binding drinking water standards for six PFAS compounds in 2024 following Rob Bilott's decades of legal work, setting limits at four parts per trillion for PFOA and PFOS.
Water Filtration Options Compared
Not all filters remove the same things. Here is an honest comparison of the main options available for home use.
Jug Filters (Brita and similar)
Good at reducing chlorine, limescale and some heavy metals. Limited effectiveness against PFAS specifically, with performance varying significantly between filter types. Cheapest entry point at around £20 to £40 for the jug plus ongoing filter replacement costs.
Best for: reducing chlorine taste and basic heavy metal reduction. Not recommended as the only filtration method if PFAS is your primary concern.
Under Sink Filters
Higher upfront cost, typically £150 to £400, but more thorough filtration. Some models are certified to remove PFAS to below detectable levels. Check for NSF 53 or NSF 58 certification specifically, which covers PFAS removal.
Best for: households wanting comprehensive filtration without changing their water habits. Requires professional installation in most cases.
Reverse Osmosis Systems
The most thorough option available for home use, removing the widest range of contaminants including PFAS, pesticide residues, heavy metals and microplastics. Important caveat: reverse osmosis also removes beneficial minerals, so a remineralisation stage is essential to restore calcium, magnesium and potassium to the filtered water. Systems with remineralisation built in are available. Cost typically £300 to £800.
Best for: the most comprehensive filtration available. The Huberman Lab audience specifically asked whether reverse osmosis with remineralisation is effective and the answer is yes, provided the remineralisation stage is included.
Steam Distillation
Water is boiled and the steam is collected and condensed, leaving behind contaminants that cannot evaporate. Removes PFAS, heavy metals, pesticides and microplastics effectively. Slower than other methods and requires electricity to run. Like reverse osmosis, distilled water is mineral-free and remineralisation is recommended.
Best for: maximum purity without plumbing installation. This is the method Dr Shanna Swan uses herself, storing the distilled water in glass containers.
What Dr Shanna Swan Does Herself
In her Huberman Lab interview, Dr Swan described using a tabletop steam distiller at home, storing the distilled water in glass containers rather than plastic. She noted that this gives her confidence about what she is actually drinking, regardless of what comes through the tap.
For most people, a reverse osmosis system with remineralisation is the most practical high-quality option that does not require changing daily habits significantly. A quality jug filter is better than no filter at all, though its limitations around PFAS specifically are worth knowing.
Whatever filtration method you choose, store filtered water in glass or stainless steel rather than plastic. Plastic bottles and containers can leach compounds into the water, particularly when the water sits for extended periods or is exposed to heat.
Related reading: our Home and Living page covers water filtration alongside other sources of household chemical exposure, and The Evidence page links to the full UK Government PFAS Plan published in February 2026.
Sources: UK Government PFAS Plan (February 2026) | US EPA PFAS Drinking Water Standards (2024) | Dr Shanna Swan, Huberman Lab interview | NSF International water filter certification standards