The human body begins to experience cognitive impairment after just 2% fluid loss — and cannot survive more than 3–5 days without water under normal conditions. Yet water is typically the least-stocked emergency resource in most households. FEMA research shows that fewer than 20% of Americans have even a 72-hour water supply at home. During Hurricane Maria in Puerto Rico in 2017, communities in some areas went without safe running water for months, with residents resorting to potentially contaminated streams and irrigation channels. Understanding water storage, purification, alternative sourcing, and sanitation without running water is not an optional add-on to emergency preparedness — it is the foundation.
Water Needs Assessment
Minimum Daily Requirements
| Purpose | Minimum Per Person | Comfortable Amount |
|---|
| Drinking | 2 litres | 3 litres |
| Food preparation | 0.5 litres | 1 litre |
| Basic hygiene | 1.5 litres | 3 litres |
| Total minimum | 4 litres/day | 7+ litres/day |
Increase by 50–100% for:
- Hot weather or physical labour
- Children, elderly, or those with medical conditions
- Pregnant or breastfeeding women
- Sick individuals
For a family of four, plan for a minimum of 16 litres per day — 112 litres for a one-week supply.
Before Disruption — Storage
Water Storage Containers
Food-grade plastic containers:
- Use only containers specifically designed for water storage or that previously held food-grade liquids.
- Never use containers that held chemicals, petrol, or non-food liquids (residues are nearly impossible to remove completely).
- 20-litre jerry cans are practical for most households.
- 200-litre barrels are highly efficient for space and cost but require a pump for access.
Commercial options:
- Pre-filled sealed water pouches and bottles (3–5 year shelf life)
- WaterBOB or similar flexible bathtub inserts (100 litres of clean tap water stored in minutes with advance notice)
Storing Tap Water
Clean tap water can be stored safely:
- Use clean, food-grade containers that have been washed with soap and water and rinsed.
- Fill directly from the tap.
- If your municipal supply is chlorinated (most are), no additional treatment is needed for storage up to 6 months.
- If not chlorinated, add 2 drops of unscented household bleach (5–8% sodium hypochlorite) per litre.
- Store in a cool, dark location away from petrol, pesticides, and strong odours (plastic absorbs vapours).
- Label containers with the fill date.
- Rotate — use and refill every 6–12 months.
Emergency Water Sources in Your Home
When water supply is disrupted unexpectedly, check these existing sources before seeking outside water:
- Water heater tank — most contain 100–300 litres of water. Turn off the power/gas first, open the drain valve at the bottom, and allow to fill a container. Water may have sediment.
- Ice in the freezer — allow to melt.
- Water in toilet tank (not the bowl) — is generally clean if no chemical tablets are used.
- Tinned food liquids — liquid from tinned vegetables and fruits is potable and can supplement water intake.
- Turn off the main water supply valve if pipes have been damaged or contamination is suspected — this prevents contaminated water from entering your system.
- Fill all available containers immediately while any remaining pressure exists.
- Stop all non-essential water use — no laundry, dishwashers, or garden irrigation.
- Note your current water supplies and calculate how long they will last at minimum daily use.
- Monitor official communications for the cause and expected duration of disruption.
Water Purification Methods
Unless water comes from a reliably tested sealed source, treat all emergency water.
Boiling
The most reliable method for biological contamination (bacteria, viruses, protozoa including Giardia and Cryptosporidium).
- Bring water to a rolling boil.
- Maintain boiling for 1 minute (3 minutes at altitudes above 2,000 metres).
- Allow to cool in a covered container.
- Aerate by pouring between containers if taste is flat.
Boiling does NOT remove chemical contamination, heavy metals, or radiological particles.
Chemical Treatment — Chlorine Bleach
Effective against bacteria and most viruses; less effective against Cryptosporidium.
Use unscented household bleach containing 5–8% sodium hypochlorite (check the label):
| Water Condition | Bleach Amount Per Litre |
|---|
| Clear water | 2 drops (0.1 mL) |
| Cloudy water | 4 drops (0.2 mL) |
Stir, then let stand for 30 minutes before drinking. Water should have a slight chlorine smell. If not, repeat the dose and wait another 15 minutes.
⚠️ Do not use bleach that contains soaps, thickeners, scents, or other additives. Do not use colour-safe bleach. Do not use bleach with less than 5% active sodium hypochlorite.
Chemical Treatment — Water Purification Tablets
Sodium dichloro-isocyanurate (NaDCC) tablets and iodine tablets are available commercially. Follow package directions. NaDCC tablets (e.g., Aquatabs) are preferred over iodine — iodine has health concerns for pregnant women and those with thyroid conditions.
Effectiveness: NaDCC kills bacteria, viruses, and most protozoa. Filter first if water is very cloudy — turbidity reduces effectiveness of chemical treatment.
Filtration
Improvised pre-filtration (removes suspended particles, not biological/chemical contamination):
- Allow water to settle for 30 minutes.
- Pour through clean fabric (cotton t-shirt, coffee filter) to remove suspended particles.
- ALWAYS follow with boiling or chemical disinfection.
Commercial filters:
- Pump filters (Sawyer, MSR, LifeStraw) remove bacteria and protozoa to 0.1 microns.
- Most do not remove viruses (viruses are smaller than most filter pores).
- Add chemical treatment after filtration for full viral protection.
- UV purifiers (SteriPen) — effective against bacteria, viruses, and protozoa in clear water. Requires batteries.
Water From Alternative Sources
| Source | Risk Level | Treatment Required |
|---|
| Municipal mains (cold, no disruption) | Low | None normally |
| Municipal mains (post-disruption, boil order issued) | Medium | Boil or disinfect |
| Private well | Variable | Test before use; treat if uncertain |
| Rainwater (clean collection, no pollution events) | Low | Boil or disinfect |
| Natural spring | Medium | Boil or disinfect |
| Moving stream/river | High | Filter, boil, and disinfect |
| Still pond/lake | High | Filter, boil, and disinfect |
| Floodwater | Very high | Do not use for drinking without laboratory-level treatment |
Water Rationing
When supplies are genuinely limited:
Priority Order
- Drinking and oral hydration (non-negotiable minimum: 2 litres/person/day)
- Medical needs (wound cleaning, medication preparation)
- Food preparation and cleaning utensils
- Basic personal hygiene (hand and face washing)
- Toilet flushing
- Other hygiene and cleaning
Practical Rationing Strategies
- Use wet wipes instead of water for personal hygiene when supply is limited.
- Cook one-pot meals that use water efficiently.
- Use paper plates to eliminate dishwashing.
- Minimise activities that increase sweating and water need.
- Reuse rinse water from cleaning for toilet flushing.
Sanitation Without Running Water
Handwashing
Handwashing remains essential even with limited water. Options:
- Tippy-tap: A small jerry can on a pivot — pressing a foot lever tips the can to release a small water stream. Uses as little as 40 mL per handwash.
- Spray bottle: Mist hands with water before applying soap; rinse with minimal water.
- Alcohol-based hand sanitiser (60%+ alcohol) when water is critically limited — note it does not remove physical contamination (chemical/radiological); only water washing does.
Toilet Without Flushing Water
- Flush manually using a bucket. Pour 5–8 litres of any water (grey water, collected rainwater, pond water) directly into the bowl — gravity does the rest.
- Compost toilet / bucket latrine if flush water is unavailable: bucket with a tight-fitting lid, lined with bags, emptied into a deep pit dug far from water sources.
- Maintain strict hygiene around toilet areas; wash hands after every use.
Waste Disposal
- Bag and seal solid waste if flush toilets are unavailable.
- If burying waste, dig a "cat hole" at least 60 metres from any water source, at least 15 cm deep.
- Feminine hygiene products and nappies generate significant waste; stock disposable bags for sealing.
Quick Reference
| Situation | Action |
|---|
| Water disruption announced | Fill all containers immediately; conserve |
| No advance warning | Water heater tank, toilet tank, stored food liquids |
| Need to purify water | Boil 1 min (first choice), or 2 drops bleach/litre |
| Cloudy water | Filter through fabric first, then boil or disinfect |
| Daily minimum per person | 4 litres (2L drinking + 2L hygiene/food) |
| No water for toilet | Pour 5–8L of any water directly into bowl |
| Handwashing with limited water | Tippy-tap, spray bottle, or hand sanitiser |
| Floodwater | Do not drink even after boiling — chemical contamination risk |
This article provides general guidance on water supply disruption preparedness. Water purification methods should be applied according to the specific contamination risk. For confirmed chemical or radiological water contamination, follow specific guidance from your water authority — boiling alone is not effective.