Storage is what turns rainfall into a dependable supply, so it is worth planning the tank, its material and its position before you buy anything.
Choose the container with care
The book gives one basic rule for any tank or container: it should be opaque and UV-resistant, which stops light getting in and helps prevent algae forming. Other materials, such as concrete or steel, can be used but should be lined with a food-grade liner so the water stays clean and safe to handle.
Decide how the water will reach the house
- Gravity-fed: raise the tank above the house so water flows down without a pump. This is simple and has little to go wrong, but it needs a suitable high spot or a sturdy stand.
- Underground with a pump: store the water below ground and use a pump to maintain a steady supply. This can protect against freezing and heat, but it adds a pump, power use and another thing to maintain.
Size it for the dry weeks
Start from your daily use (see how to estimate your water needs) and multiply by the longest dry stretch you realistically expect. Then compare that with what your roof can collect over a year, as in rainwater collection planning. If you plan to keep a fire suppression reserve, which the book lists among water uses, hold that volume back as a separate figure.
Plan for winter at the start
If your area freezes, the book advises finding the depth at which the ground begins to freeze, typically about 1 to 4 feet (roughly 0.3 to 1.2 metres), and checking local building codes. Keep pipes below that depth or protected, and insulate above-ground tanks with thick foam. More detail is in protecting stored water.
Checklist before you buy
- Opaque and UV-resistant, or lined with a food-grade liner.
- Volume that covers your longest dry spell plus any reserve.
- Gravity or pumped delivery chosen deliberately.
- Access for cleaning and inspection.
- Protection from freezing and from contamination.
The Off-Grid Water guide covers storage alongside collection, treatment and winter protection. For the DIY side of building these systems yourself, see The Off-Grid Survival Manual.