Most households discover their water plan is inadequate on the second day of an outage. Here is how to think about it before that happens, starting with the cheapest steps.

Start with what you actually need

Planning figures worth knowing, because guessing produces either panic-buying or dangerous under-preparation.

The gap between the top and bottom rows is the whole reason storage plans fail. A family of four using 200 litres each per day gets through a 2,500-litre tank in three days without changing anything. Rationed to drinking and cooking only, the same tank lasts weeks.

The three tiers, in the order to do them

Tier one — cheap, do it this week

• Store 25 litres of drinking water per person. Food-grade containers, somewhere cool and dark, rotated every six months. This is the highest-value thing on this entire page and costs almost nothing.
• Fill containers when an outage is announced. Baths, buckets, bottles. Ten minutes of warning is worth hundreds of litres.
• Know where your municipality's water tankers deploy during outages, and keep containers you can actually carry.
• Keep the means to treat water — a kettle for boiling, or purification tablets. Boiling for one minute at a rolling boil handles the microbiological risk that follows most supply interruptions.

Tier two — moderate cost, handles days

• A storage tank. The standard answer, and it works well for what it is: a buffer for short interruptions. Fitted to fill automatically from the municipal line, it gives you days without you doing anything.
• Rainwater harvesting. Cheap per litre if you have roof area, seasonal, and needs treatment before drinking. Excellent for flushing and washing regardless.
• A greywater plan. Not glamorous, but toilet flushing is your biggest consumer and it does not need clean water. Separating that use alone can triple how long your stored drinking water lasts.

Tier three — significant cost, handles indefinite outages

• A borehole, where geology and permits allow. The highest capacity option. Needs power, needs testing, and the water quality is whatever the ground gives you.
• An atmospheric water generator. Produces drinking water from air, independent of any supply line. Drinking quantities rather than utility volumes, and it needs electricity.

Storage versus generation — the distinction that matters

Nearly all water security advice conflates two different things.

Storage buys time. A tank holds water you already received. When the supply stops, it drains at whatever rate you use it and then it is empty. Storage is excellent for a burst main or a day of maintenance, and useless for a sustained failure.

Generation and extraction produce new water. A borehole extracts it from the ground; an atmospheric water generator condenses it from air. Neither runs out while it has power, which makes them the only answers to an outage of unknown length.

The sensible household setup uses both: storage as the immediate buffer, and a source for anything beyond a few days. They are not competing purchases.

What actually fails during an outage

From how these events actually unfold, in order:

1. Day one is fine. Pressure drops, the tank or stored water covers it, nobody changes behaviour.
2. Day two, usage discipline collapses. Somebody flushes without thinking, somebody showers. Storage empties far faster than the plan assumed.
3. Day three, the tank is empty and the shops have no bottled water, because everyone in the suburb had the same plan.
4. Then it becomes a logistics problem — queuing at tankers, carrying containers, and discovering that 25 litres weighs 25 kilograms.
5. When supply returns, the water is often not safe immediately. Pressure loss draws contamination into pipes, which is why boil-water notices follow outages.

That last point is under-appreciated. The risk window does not close when the water comes back on.

Where a generator fits, honestly

It is not a whole-house solution and we would not sell it as one. A 20L or 80L machine produces drinking and cooking quantities, not enough to flush toilets or run a household normally.

What it does is remove the drinking water problem permanently — the one that actually matters for health and the one that sends you queuing at a tanker. Everything else during an outage can be handled with stored water, greywater and rationing. Drinking water is the part that cannot.

It also works in the reverse case: when the supply is running but of poor quality, or after an outage when a boil-water notice is in force, the same machine purifies whatever you do have.

If you can only do one thing after reading this, store 25 litres per person. That costs almost nothing and covers the most likely scenario. The rest is a question of how long an outage you are preparing for.

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