Why your tap water tastes like a swimming pool
That faint swimming-pool taste is chlorine, and it is actually a sign your water is being looked after. Here is why it is there, why it lingers, and how a simple carbon filter removes it at the tap.
4 min read
First, the good news: that chlorine is there on purpose
Before water leaves the municipal treatment works, a small, carefully measured dose of chlorine is added to it. Its job is to kill germs, both at the works and all the way along the kilometres of pipes between the reservoir and your kitchen. Chlorinating drinking water is one of the great public-health successes of the last century, and it is the reason you can pour a glass straight from a municipal tap without a second thought.
Here is the part most people don't know: the dose is deliberately set so that a little chlorine is still left in the water when it reaches your home. That leftover chlorine (engineers call it a residual) is proof the protection is still working right up to your tap. No chlorine at the tap would actually be the worrying sign.
So if your water smells faintly of a swimming pool, the chlorine itself is not a fault: a residual is supposed to be there. One honest caution: the smell is not a water-quality test in either direction. It tells you disinfectant is present, not that everything else about the water is right. By the time it reaches your glass most of its protective travelling is done, and now it is largely a taste and smell you would rather not have in your tea.
So why does it taste and smell like a pool?
Chlorine belongs to the same chemical family as pool sanitiser, and the human nose is remarkably good at picking it up — even in tiny amounts. Some people barely notice it; others can taste it in their morning coffee. The strength can also vary from day to day and season to season, depending on how much chlorine was dosed and how far the water has travelled to reach you.
There is a second character in this story: chloramine. Some water supplies combine chlorine with a small amount of ammonia, creating a longer-lasting disinfectant called chloramine. From the municipality's point of view this is a feature, because it keeps protecting the water further down the line. From your kitchen's point of view, it is more stubborn.
That stubbornness explains a common frustration. Plain chlorine slowly escapes from a jug of water left standing overnight, which is why your gran's fridge-jug trick sometimes works. Chloramine, on the other hand, mostly stays put. If letting your water stand doesn't improve the taste, chloramine is a likely reason. It is also a harder job than plain chlorine, needing the right carbon media and enough contact time. If chloramine is your suspect, ask us about the right cartridge rather than assuming any carbon filter will handle it.
How activated carbon takes it out (in plain words)
The tool for this job is activated carbon — essentially charcoal that has been specially treated until it is riddled with microscopic tunnels and pockets. All those tiny surfaces act a bit like Velcro for the compounds behind off-tastes and odours: they stick to the carbon and stay behind while the water carries on to your glass. With free chlorine the carbon is actually a little cleverer than Velcro. Its surface reacts with the chlorine and neutralises it, rather than only storing it, which is part of why a good carbon stage handles as much chlorine as it does.
Carbon comes in two forms, and the names are simpler than they sound. Granular activated carbon (GAC) is loose granules, a bit like coarsely ground coffee packed into a cartridge. Water flows through it easily, so it suits systems where you want a strong, steady flow. A carbon block is the same carbon compressed into one dense, solid cylinder. Water has to work its way through slowly and evenly, which gives the chlorine more contact time with the carbon, and the dense block catches fine particles as a bonus.
Neither is 'the good one'. They are teammates, and many systems use both: GAC to do the heavy lifting, a carbon block to polish the taste. One honest note: because carbon works by holding on to what it catches, every cartridge eventually fills up. Carbon cartridges should be replaced at their stated time or litre limit, whichever comes first (typically every 3 to 6 months), which is exactly why our filters come with replacement reminders.
Which SUPERPURE filter fixes it in your home
If the taste bothers you at the kitchen tap, an under-counter system is the classic fix: it sits out of sight beneath the sink, and its carbon and carbon-block stages remove the chlorine taste and odour before the water reaches your glass. Renting, or can't touch the plumbing? A countertop unit does the same job with no installation at all.
If you would rather sort out every tap at once, a whole-house system treats the water where it enters your home, so drinking water, showers and appliances all benefit. One trade-off worth knowing: removing chlorine at the point of entry also removes its protective residual from the pipes inside your house, which suits homes with sound plumbing and regular use. Water that then stands for weeks in seldom-used lines no longer has that protection. And chlorine isn't only a taste issue. If showering leaves your skin feeling tight or your hair dull, a shower filter screws on in minutes and reduces chlorine before the water reaches you.
Already filtering? Fridges with water dispensers and filter jugs rely on small carbon cartridges of their own, and SUPERPURE makes compatible replacements for the big-name originals. And if you own a filter system that has started tasting of pool again, that is usually just a tired cartridge — a fresh carbon block restores the taste.
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