Simple breakdowns on microplastics, tap chemicals, and easy ways to get clean, crisp water at home.
Every guide here falls under one of these.
pfas · microplastics · lead in water · tap water testing
reverse osmosis · water filter · carbon block · micron rating
hard water · water softener · shower filter · limescale
Easy-to-read guides to help you make sense of tap and bottled water.
What the hard crust inside a boiler actually is, why heat is what makes it form, which parts of a heating system it lands on, and why the hardness of your supply decides whether you ever see it.
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Hard water stains are the dissolved minerals your water leaves behind once it evaporates. This explains what the white spots and films are made of, where the minerals come from, what the hardness number on a water report means, and why a mild acid shifts the deposit when scrubbing does not.
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Limescale is calcium carbonate left behind when hard water is heated or dries out. This explains where the minerals come from, why the kettle and the shower head get it first, how hardness is measured, and what physically removes scale or stops it forming.
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A shower filter is a chlorine-reduction cartridge working at a very awkward flow rate, and it has no mechanism at all for taking calcium and magnesium out of hot water. This explains what is inside one, why contact time is the whole problem, and why limescale on the glass and the nozzles is untouched by it.
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A water softener is an ion-exchange machine, not a filter. This explains what happens inside the resin tank, why the thing needs a sack of salt, and what softened water contains that hard water did not.
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An under-sink filter is a sealed cylinder plumbed into the cold pipe inside the cabinet, so every drop reaching the tap is forced through the cartridge by mains pressure. This explains each part, why it is teed into the cold line, what carbon and membranes physically do, and what changes as a cartridge loads up.
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A plain explanation of how a carbon block filter works: what activated carbon is, why the carbon is pressed into a solid cylinder instead of left loose, what sticks to it, and what passes straight through untouched.
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A plain explanation of how reverse osmosis works: the pressure, the membrane, the filters either side of it, the water that goes to the drain, and how what it removes lines up with the limits regulators publish.
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The two ways to find out what is in your tap water: the annual report your water supplier already publishes, and a sample from your own tap analysed by a certified laboratory. What each one covers, what the units and limits mean, and which one answers your question.
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Lead in drinking water comes from the pipes and fittings between the water main and your tap, not from the source or the treatment works. This explains how it gets in, what limits regulators have set, why boiling does nothing, and what a filter physically does to a dissolved metal.
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Hardness is dissolved calcium and magnesium, picked up from rock. This explains how the measurement works, why regulators class it as a nuisance rather than a health matter, what it genuinely costs you around the house, and why it is the one thing a cheap handheld meter is actually measuring.
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Plastic particles have been found in tap water, bottled water and bottled water's own packaging. This sets out what the World Health Organization concluded, why the counts reported in the news vary so wildly, and why pore size is the right question to ask about plastic but not about most other contaminants.
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PFAS are a large family of synthetic fluorinated chemicals used to make surfaces repel water and grease. This explains where they come from, what the US Environmental Protection Agency now requires water systems to do about them, and why the two kitchen habits people reach for first are the wrong ones.
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A filter is a sieve with a measured hole size. This explains what a micron is, why a smaller number is not automatically better, and why the things people worry about most are often the things a sieve cannot catch at all.
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A jug filter and an under-sink system can contain similar carbon and perform very differently. This explains the two physical variables that account for most of the gap, why a TDS meter cannot tell you whether either one is working, and what a jug is genuinely good at.
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