Hydration Decoded: What's Really in your Glass?

Water is the lifeblood of our bodies, making up about 70% of our weight. It cushions joints, regulates temperature, flushes toxins, and powers up our cells. With overflowing hydration options; from filtered pitchers to electrolyte drops and the ever-debated daily water target it’s fair to ask what kind of water should we actually be drinking, and how much do we really need?

Tap water

Tap water is convenient, regulated, and for many a daily staple. But while it technically meets safety standards, that doesn’t always mean it’s free from things we wouldn’t choose to drink.

Most standard water supplies contain chlorine (used to kill bacteria), fluoride (added for dental health), and trace amounts of contaminants like microplastics, heavy metals, and even pharmaceutical residues. These are by-products of the treatment process or remnants of ageing infrastructure, and while they’re classed as being within “acceptable” levels, growing evidence suggests even small, chronic exposures can add up; especially in vulnerable individuals like children or those with weakened immune systems.

Hard water regions do offer a silver lining, with naturally occurring minerals like calcium and magnesium that can benefit bone and heart health. But if you're aiming for the cleanest, most mineral-rich hydration, many people opt for some level of home filtration to reduce chemical load and improve taste.

Tap water is a starting point but it’s worth thinking about what’s flowing from your faucet day after day.

Filtered water

Filter jugs, plumbed in filters, under-sink systems; filtered water is big business. These filters can improve taste, reduce chlorine, and remove sediment as well as some also reducing heavy metals like lead or mercury which is especially important in areas and houses with older pipes.

The catch though is that basic filters don’t remove everything. They may leave behind many naturally occurring minerals (which is a good thing), but they also won’t touch certain bacteria or dissolved solids unless they’re specifically designed to.

So while filtration makes water cleaner and often tastier, it doesn’t always make it more hydrating or significantly healthier.

Reverse osmosis

Reverse osmosis (RO) systems take filtering to another level. By forcing water through a semipermeable membrane, RO strips out nearly everything - chemicals, salts, minerals, and even bacteria. The result? Ultra-pure water.

This sounds great on paper, but RO removes beneficial minerals like calcium, potassium, and magnesium too. Long-term reliance on RO water, without re-mineralisation (where you add your own minerals back into your water after filtering), could potentially contribute to mineral deficiencies, particularly if your diet is low in these nutrients to begin with.

Some RO systems now come with re-mineralisation cartridges that add key electrolytes back in - something to look for if you're opting for this option.

Electrolytes

If you’ve ever bounced back from a workout (or a hangover) thanks to a sports drink or electrolyte tablet, you already know electrolytes matter. These amazing minerals (mainly sodium, potassium, magnesium, and calcium) help your body retain water, support nerve signals, and balance pH levels.

But do you need to add them to your water every day?

If you sweat a lot (hello hot yoga), live in a hot climate, or are feeling under the weather, a little boost can go a long way. But for most people, a balanced diet and regular water will cover your needs. Overdoing electrolyte supplements (especially sodium) can actually work against you, raising blood pressure or causing bloating.

Pro tip: coconut water, leafy greens, nuts, and seeds are all natural ways to keep electrolyte levels topped up, no sachet needed.

8 glasses a day?

The old “8 glasses a day” advice? It’s more folklore than fact.

According to research, hydration needs vary by body size, activity level, climate, and diet. A 2023 study published in Science found that adults typically need 2.5 to 3.5 litres per day, but around 20-30% of that comes from food (especially fruits and veggies).

A more personalised approach is this: drink when you’re thirsty, and let your urine be your guide. Pale yellow is ideal. If it’s dark? Time to sip. If it's completely clear all day, you might be overdoing it.

And remember, tea, coffee, milk, and even soup all count toward your fluid intake - hydration isn't just what’s in your water bottle.

Whether you're pouring straight from the tap, sipping filtered water, or adding a dash of sea salt and lemon to your bottle, what matters most is consistency. Your body thrives on steady hydration; not just on hot days or after a sweaty workout.