How much should you drink?
The "8 glasses a day" advice is a useful floor, not a ceiling. A reasonable target is about half your bodyweight in ounces per day — more if you sweat heavily, live in a dry climate, drink coffee or alcohol, or eat a low-water diet. Your urine should be the color of pale straw.
Signs you're under-hydrated
- Headaches, especially mid-afternoon
- Brain fog or low energy that "improves with coffee"
- Dark yellow urine, infrequent urination
- Constipation, dry skin, dry lips
- Crashing during workouts
Tap vs filtered vs bottled
Municipal water in the US is regulated for ~90 contaminants — but research routinely finds lead from old service lines, chlorine disinfection byproducts, PFAS ("forever chemicals"), microplastics, pesticide residue, and pharmaceutical residue at levels that may pose long-term risk even when "in compliance." Bottled water is unregulated relative to tap, often is tap, and adds plastic exposure on top.
Choosing a filter
| Type | Removes | Best for |
|---|---|---|
| Pitcher (carbon) | Chlorine, taste, some lead | Renters, low budget |
| Under-sink carbon block | Chlorine, VOCs, lead, some PFAS | Most homes |
| Reverse osmosis | Almost everything (incl. PFAS, fluoride, nitrates) | Best protection — pair with a remineralizer |
| Whole-house | Sediment, chlorine, some heavy metals | Homeowners, well water |
Electrolytes — when they matter
Plain water plus a balanced diet is enough for most people. You may want extra sodium, potassium, and magnesium if you're: training hard, sweating a lot, drinking primarily filtered water, eating low-carb, or recovering from illness. A pinch of sea salt and a squeeze of lemon in your morning glass covers most everyday needs.
Containers
Glass and stainless steel only. Avoid drinking hot beverages from plastic and never reheat food in plastic. See the Carcinogens guide for more.
Recommended gear
Berkey / AquaTru
Countertop options that go far beyond a basic carbon pitcher.
Klean Kanteen / Hydro Flask
Insulated stainless steel; lasts a decade.
LMNT or DIY
1 g sodium, 200 mg potassium, 60 mg magnesium per serving — or mix your own for cents.
Under-sink RO + remineralizer
The gold standard for home drinking water.
Quick-win checklist
- Drink a full glass first thing in the morning, before coffee.
- Keep a glass or stainless bottle on your desk; refill it 4× a day.
- Filter your tap. At minimum a carbon block.
- Read your annual local water-quality report.
- If you sweat hard, add a pinch of salt and squeeze of lemon to one glass.