Tap water tastes different from town to town, and sometimes from tap to tap within the same town, depending on which part of the distribution system it came through recently. Two of the most common reasons are chlorine (or chloramine) and total dissolved solids, usually shortened to TDS. Neither one is inherently a safety problem – TDS describes dissolved material, while chlorine or chloramine may be used for disinfection – but both affect taste, and that's usually what people notice first. We’ll explain how each affects the water you taste.
What TDS Means, in Plain Terms
Total dissolved solids is a measure of everything dissolved in water that isn't water itself – minerals like calcium, magnesium, and sodium, along with smaller amounts of other dissolved compounds. It's measured in parts per million (ppm), and it's a broad indicator rather than a measure of any one specific substance. Water with higher TDS tends to taste "heavier" or more mineral-forward; water with lower TDS tends to taste cleaner or flatter, depending on your palate. Neither high nor low TDS by itself indicates whether water is safe – safety depends on what the dissolved solids actually are, not just how many there are.
It helps to know roughly how TDS is measured in practice, since the concept can otherwise feel abstract. A TDS meter works by measuring the electrical conductivity of water – dissolved minerals and salts conduct electricity, and pure water with nothing dissolved in it barely conducts at all – then converting that conductivity reading into an estimated ppm figure. It's a fast, practical field measurement, but it's worth understanding its limits: a TDS meter tells you roughly how much is dissolved in the water, not what it is, so two samples with an identical TDS reading could have meaningfully different mineral profiles. That's part of why TDS is best understood as one useful data point about water character, not a complete safety test on its own.
Why Chlorine Shows Up in Taste and Smell
Chlorine and chloramine are added to municipal water specifically to keep it safe as it travels through the distribution system to your tap – without them, water would be far more vulnerable to bacterial contamination between the treatment plant and your home. The tradeoff is that both compounds have a distinct taste and smell that many people notice, especially in water that's sat in pipes for a while or that's being tasted right after a maintenance event added a fresh dose. This is one of the most common reasons people describe tap water as tasting "like a pool" or "chemical" – taste alone cannot establish safety, and an unexpected change should be raised with the water supplier, and it's exactly what carbon filtration is designed to address.
Chlorine and chloramine aren't interchangeable, even though they're often talked about as if they were. Chlorine dissipates relatively quickly once water is exposed to air – which is part of why letting a glass of tap water sit uncovered for a while can reduce a chlorine taste somewhat. Chloramine, a compound of chlorine and ammonia, is more stable and doesn't dissipate the same way, which is one reason some municipal systems have shifted toward it for longer-lasting disinfection through the distribution system – but it also means simply letting chloraminated water sit out isn't an effective way to reduce its taste the way it can be with straight chlorine. A carbon system must be selected for the particular disinfectant and conditions; do not assume every carbon filter has the same chloramine performance.
Hardness, Sediment, and Seasonal Changes
Water hardness mainly reflects dissolved calcium and magnesium. It can affect scaling and soap performance, but a hardness or TDS reading is not a complete water-quality test. Source conditions, treatment and distribution-system work can affect taste or appearance.
Do not assume that a sudden change will clear on its own or is harmless. Contact your water supplier about unexpected colour, odour or taste and follow current official notices. Local water-quality reports give better context than a general regional description.
How Purification Changes the Picture
Sediment filtration targets particles; selected carbon systems can address taste and odour; RO can reduce specified dissolved substances; and UV addresses microorganisms within its rated operating conditions. H2OtoGo describes these stages on its website. The outcome depends on the equipment, source water and maintenance, so this is not a promise of identical taste or complete contaminant removal at every refill.
A preference for a particular taste is separate from the question of whether water meets health requirements. A TDS meter, clear appearance or taste comparison cannot answer that safety question alone.
FAQ
Is high TDS water unsafe to drink?
Not inherently – TDS measures quantity of dissolved solids, not what they are; municipal water that meets safety standards can have a wide range of TDS levels.
Why does my tap water taste different after a rainstorm?
There can be several causes. Contact your water supplier about an unexpected change and check current notices rather than assuming rain explains it.
Does refill-station water have a consistent taste?
Consistency is one of the main goals of multi-stage purification – treating water the same way, stage by stage, regardless of small day-to-day variation in the source water.
What's a "normal" TDS reading for tap water?
TDS in municipal tap water commonly ranges anywhere from under 50 ppm to several hundred ppm depending on the region's geology and water source, so there isn't a single "normal" number – what matters more is whether the water meets applicable safety standards, which TDS alone doesn't determine.
Can I taste the difference between chlorine and chloramine?
Many people can, though it varies by sensitivity – chlorine is often described as sharper or more "pool-like," while chloramine is sometimes described as more of a persistent, muted chemical taste, though descriptions vary widely from person to person.
Does boiling tap water remove chlorine taste?
Boiling can help dissipate chlorine somewhat, similar to letting water sit out, but it's far less effective against chloramine and does nothing to reduce TDS, which is why filtration is a more complete approach for taste specifically.
Why does bottled water sometimes taste different from refill-station water even though both are purified?
Different bottled water brands source from different water bodies and may use different treatment processes or add minerals back in after purification, so taste can vary by brand in ways that don't necessarily indicate anything about relative quality.
Visit your local H2OtoGo station for your next refill.