Water purification: simple ways to make your drinking water safe

Contaminated water can make you seriously sick. Around 2 billion people worldwide don’t have reliably safe drinking water, so knowing a few practical purification methods matters—even if your tap usually seems fine. This page gives clear, usable steps you can apply at home, on the road, or during an emergency.

Everyday methods that work

Boiling: the easiest fail-safe. Bring water to a rolling boil for 1 minute. If you’re above 2,000 meters (6,500 feet), boil for 3 minutes. Boiling kills bacteria, viruses, and most parasites but won’t remove chemicals or heavy metals.

Filters: good ones remove particles, bad tastes, and many microbes. A basic ceramic or carbon filter will improve taste and remove chlorine and sediment. If you’re worried about bacteria and protozoa, look for filters rated to 0.1–0.3 microns. For chemicals and metals, choose a reverse osmosis (RO) or specialized media filter. Replace cartridges on schedule—filters work poorly when clogged.

Chemical disinfection: chlorine and iodine tablets are light and cheap for trips. Use regular unscented household bleach (5–6% sodium hypochlorite): about 8 drops per gallon (roughly 2 drops per liter), mix, and wait 30 minutes. Iodine works similarly but isn’t ideal for pregnant people or long-term use.

UV and solar: portable UV pens (battery-powered) zap microbes quickly and leave no taste. Solar disinfection (SODIS) uses clear plastic bottles left in full sun for 6 hours (longer if cloudy) — a low-cost option that works best on clear water with low turbidity.

Choosing the right approach and keeping water safe

Match the method to the threat. If your water smells or tastes chemically, a carbon filter or RO system helps. If the risk is microbial (outdoor water, flood, well problems), boil or use a certified microfilter or UV device. For cloudy water, always pre-filter through a cloth or let sediment settle before other treatments.

Test your water when you can. Home test kits can check bacteria, nitrates, or lead. For a full picture, send a sample to a certified lab. Keep replacement parts on hand—old cartridges, dead batteries for UV pens, or expired tablets defeat the whole system.

Emergency checklist: strain out large debris, then boil or chemically treat. Store treated water in clean, food-grade containers and label them. Rotate stored water every 6–12 months. If local authorities issue a boil-water notice, follow it immediately.

Practical habits matter: clean pitchers and bottles regularly, don’t drink from stagnant or questionable sources without treating, and read product labels for filter certifications (NSF/ANSI ratings are good). A small investment in the right filter or a few tablets can prevent a lot of headaches—and keep you drinking safe water no matter where you are.