Louise stopped drinking pat h2o astir 12 years ago.
Since then, she has spent hundreds of pounds connected each mode of at-home filtration systems successful a bid to easiness her anxieties astir h2o quality.
"It's ever been a interest for me," the 34-year-old nurse, from Greater Manchester, tells Sky News.
"In my enactment of work, I woody with a batch of bacteria. E-coli, legionella, norovirus - and they tin each travel from water. It's a scary thought."
She says that portion her worries whitethorn conscionable beryllium "speculation" - and determination are strict rules connected manus hygiene and corruption power connected her NHS ward - h2o has been a "personal concern" for much than a decade.
Women, well-educated and city-dwellers are astir worried
A survey published past twelvemonth showed 52.3% of radical crossed 141 countries were disquieted astir being harmed by their drinking h2o successful the adjacent 2 years.
The research, which utilized 2019 polling information from much than 148,000 people, besides recovered that h2o concerns were much communal among women, radical who unrecorded successful municipality areas, those with higher levels of education, and radical experiencing fiscal difficulties.
In the UK, much than 20% reported being worried, portion the latest spot successful h2o survey by regulator OFWAT besides showed spot successful h2o companies had dropped to 65% by the extremity of 2022 - compared with 76% astatine the opening of that year.
Claire, 59, from Cheltenham, says she stopped drinking pat h2o aft her begetter was diagnosed with Parkinson's illness and crab much than a decennary ago.
"My begetter is precise unwell," she says. "And precise aboriginal connected successful his attraction 1 of the consultants told him making tiny changes would assistance - eating integrated nutrient and drinking filtered water."
Her parents bought a filter jug and an under-sink filtration strategy - and she soon followed suit.
Claire says she besides questioned section h2o prime aft the 2007 flash flooding crossed Gloucestershire near her and her neighbours without drinking h2o for 3 weeks.
When the River Severn flooded, the contaminated floodwater inundated the section attraction plant, leaving supplies undrinkable.
Read more
PFAs recovered successful nutrient and portion samples
What went incorrect with Britain's h2o system?
New h2o manufacture reappraisal launched
"When the h2o got turned backmost connected - the odor that came retired of the pat was unbelievable," she recalls.
"The magnitude of chemicals they were having to pump into the pat to marque it drinkable."
Last May, a damaged aerial valve successful South West Water's web allowed the parasite cryptosporidium to get into a reservoir adjacent Brixham, Devon - which near galore with a diarrhoea bug and 17,000 households without water for 8 weeks.
Illness-inducing pathogens are 'rare'
The UK's Drinking Water Inspectorate (DWI) and different regulatory agencies elsewhere use precise strict rules to marque definite microbial contaminants similar bacteria and viruses and chemic contaminants specified arsenic metals and pesticides are removed, says Professor Luisa Orsini, prof of evolutionary systems biology and biology omics astatine the University of Birmingham.
Her colleague, Dr Mohamed Abdallah, subordinate prof of biology sciences, adds: "The tolerance is astir zero for immoderate of those pathogens successful drinking water.
"But our probe shows that portion the DWI is blessed astir the things they are monitoring - determination are things that are not being monitored."
Forever chemicals (PFAs) are 'silent killers'
Perfluoroalkyl and polyfluoroalkyl substances (PFAs) are a radical of astir 10,000 "forever chemicals", truthful called due to the fact that determination is small grounds they biodegrade implicit time.
They are utilized to marque home and concern products including carpets, level polish, frying pans, cosmetics, and nutrient packaging.
A survey by the experts' squad astatine the University of Birmingham recovered 10 people PFAs contiguous successful 99% of pat and bottled h2o samples taken from cities successful the UK and 14 different countries.
While substances similar cryptosporidium and E.coli tin beryllium deadly for radical with weakened immune systems, portion precise unpleasant, their impacts are contiguous and for astir radical comparatively short-lived.
But PFAs person been linked to respective cancers, Parkinson's disease, reduced fertility, and absorption to some antibiotics and vaccines. Infants are peculiarly susceptible arsenic their tense and immune systems are not afloat formed.
"Forever chemicals are soundless killers," Professor Orsini says. "They person precise beardown adverse effects implicit clip adjacent astatine precise debased doses - and that's the connection we privation to stock from our research."
According to the experts, PFAs are peculiarly concerning for the dual crushed that the UK's existent wastewater attraction exertion is not capable successful removing them - and regularisation is not strict enough.
Most works person a superior and secondary attraction process, which is businesslike astatine getting escaped of pathogens and immoderate chemicals - but not PFAs arsenic they are highly persistent.
Tertiary attraction is truthful needed to region them, adjacent erstwhile they hap astatine precise debased levels, says Prof Orsini.
The academics and their squad person developed a tertiary attraction that tin trim PFAs, different toxic chemicals, and pesticides successful wastewater by utilizing tiny h2o fleas - known arsenic daphnia - to hoover them up.
They reason this is simply a better, environmentally affable alternate to immoderate of the energy-intensive systems presently being developed.
No ineligible work to region PFAs
As for regulation, determination is nary statutory request for h2o companies to region PFAs successful England and Wales. The World Health Organisation has nary model for them either, but recommends countries purpose for "concentrations that are arsenic debased arsenic reasonably practical".
Before Brexit, the UK was going to follow a bounds of 0.1 micrograms per litre - the equivalent of 1 portion per cardinal - successful enactment with the European Union.
This is the existent guidance successful England and Wales - but determination is nary ineligible requirement. Last year, Scotland introduced the 0.1 micrograms per litre modular successful instrumentality for 20 PFAs.
Earlier this year, the US Environmental Protection Agency enforced overmuch stricter rules - a maximum bounds of 0.4 nanograms per litre - oregon 4 parts per trillion - due to the fact that of the imaginable quality harm.
Prof Orsini and Dr Abdallah are among 50 scientists who person written to the authorities calling for stricter, statutory regularisation connected PFAs.
A cross-party measure has present been enactment guardant by Liberal Democrat MP Munira Wilson and volition get a 2nd speechmaking successful the Commons.
But Professor Ian Cousins, an biology chemist astatine Stockholm University successful Sweden who besides signed the letter, warns: "Because the UK has been dilatory successful acting connected PFAs pollution, galore British radical person been unnecessarily and unknowingly exposed to a full cocktail of PFAs."
Sky News has contacted the Department for Environment, Food and Rural Affairs for further comment.
At-home filters region 'considerable amount'
Feeling worried?
"It's not each doom and gloom," Dr Abdallah says.
"There are elemental things that tin beryllium done astatine location to help.
"Carbon filters - either cartridges you bargain oregon those already fitted successful fridges that dispense h2o - are businesslike successful removing PFAs."
Both experts accidental they usage these kinds of filters themselves.
"Carbon filtration removes a sizeable magnitude of antithetic contaminants - including PFAs - which is bully quality for everyone who's disquieted astir it, including myself," Dr Abdallah adds.
At-home filter systems either travel successful jug, oregon countertop form, oregon they connect straight to the tap, oregon the pipes nether the sink. They alteration successful terms from astir £50 to £350.
Reverse osmosis filters, which region each impurities, are overmuch much expensive, and often request to beryllium installed extracurricular - straight wherever h2o enters the home.
They besides region immoderate of the beneficial minerals successful water, nevertheless - specified arsenic zinc and calcium - but these tin beryllium restored either by the strategy itself oregon successful droplets you tin buy.
In immoderate parts of the world, and erstwhile bugs are recovered successful the h2o proviso successful the UK, radical boil their h2o to get escaped of pathogens.
But probe shows that boiling lone removes microbial contaminants - and volition not destruct PFAs.
What astir bottled water?
For the past 5 years, Raza, 26, his parents, and his siblings person been buying their h2o - and not drinking immoderate from the tap.
The family, who unrecorded successful London, bargain astir 3 packs of six two-litre bottles a week.
Raza, who works arsenic an advisor astatine a humanitarian deliberation tank, says helium made the archetypal determination to assistance summation and show his h2o intake - having suffered kidney problems arsenic a teenager.
"It encourages maine to portion more," helium tells Sky News. "It's a benignant of unit to decorativeness the vessel - and allows maine to way however overmuch I've drunk passim the day."
He says travelling a batch - to countries wherever bottled h2o is considered the golden modular - and media reports of h2o supplies getting contaminated person "reinforced" his bottled h2o habit.
But what bash the experts say?
Bottled h2o has its ain regulations - but they enforce the aforesaid limits connected pathogens and chemicals arsenic those for pat water.
Testing and enforcement are down to the Food Standards Agency and section councils - but this is based connected typical sampling - truthful not each vessel connected the shelves is tested.
"People thin to deliberation h2o from the pat isn't arsenic harmless arsenic h2o from a vessel - but precisely the other is true," Prof Orsini says.
"Tap h2o goes done regular and stringent controls earlier it's adjacent distributed - truthful it's mode safer than immoderate different source.
"Bottled h2o besides runs the hazard of exposing you to microplastics - truthful pat is the amended enactment - particularly erstwhile combined with filtering."
From past twelvemonth bottled h2o manufacturers person had to beryllium compliance with the 0.1 micrograms per litre guidance bounds connected PFAs arsenic portion of their concern plans.