How to Choose the Right Water Tank for Your Home

In short: work out how much water your household uses in a day, decide how many days you want to hold, add a margin, and buy the smallest tank that covers it. Then check the wall and check where it will stand.

Most people do this the other way round — they pick a size that sounds right, and find out in the dry season whether it was. The arithmetic takes two minutes.

Step 1: how much do you use in a day?

A reasonable planning figure for a Kenyan household with indoor plumbing is 50 to 100 litres per person per day. Use the lower end if you are careful and the upper end if you have a washing machine, a garden or long showers.

So a family of five, moderately careful: five people × 80 litres = 400 litres a day.

Add anything that isn't household use:

• Livestock — a dairy cow drinks a lot more than you expect
• Irrigation — even a small shamba on drip adds up quickly
• A rental block — count every tenant, not every unit

Step 2: how many days do you want to hold?

This is the question that actually decides the size, and only you can answer it.

Your situation	Days worth holding
Reliable mains, occasional short cut	2 days
Mains that fail regularly	3–4 days
Borehole or a delivery you schedule	5–7 days
Rain harvesting through a dry season	Sized on rainfall, not on days

Our family of five wanting three days: 400 × 3 = 1,200 litres.

Step 3: add a margin, then round up

Nobody's usage is flat. Guests arrive, a pipe leaks, the mains stay off a day longer than expected. Add around 15%, then round up to a size that exists.

1,200 + 15% = 1,380 litres → buy a 1,500-litre tank, or a 2,000 if the budget stretches.

Round up, never down. Running dry is a worse failure than carrying spare capacity.

The Tank Sizer does all three steps for you, including the rainfall maths if you are harvesting off a roof.

Step 4: check the tank itself

Sizing right and buying badly gets you nowhere. Four checks:

• UV-stabilised outer wall. Kenyan sun destroys unprotected polyethylene.
• Food-grade inner surface. It is the only surface your water touches.
• Even wall thickness. A full 5,000-litre tank holds five tonnes.
• A warranty with years on it. Jumbo Tanks carry 16.

Step 5: work out where it will stand

This part gets skipped and then costs money.

The base. A tank needs a flat, level, fully supported base — concrete slab or compacted murram with sand. Not blocks under the edges. Not partly on soil. The floor carries the whole load and an unsupported section will deform.

Height for gravity. Every metre of height gives you roughly 0.1 bar of pressure. A tank on a tower feeds taps and drip lines without a pump; a tank on the ground usually will not.

Getting it in. Measure your gate and the path to the base before ordering. A 10,000-litre tank is wider than a lot of gates. This is the most common practical problem with a large tank, and it is entirely avoidable with a tape measure.

Filling and cleaning access. You will need to reach the lid.

Popular sizes and who buys them

Size	Typically
1,000 L	Small household, or a top-up tank beside a bigger one
2,000–2,500 L	Family of four to six on mains
3,000 L	Family plus a garden
5,000 L	Large household, small rental block, small farm
10,000 L	Farms, schools, clinics, guest houses

Two tanks plumbed together are often better than one large one: you can buy the second later, and cleaning one doesn't leave you with nothing.

The short version

Litres a day × days of cover × 1.15, rounded up to a real size. Check the wall. Check the base, the gate and the height. Then buy.

Size yours now, or send us your numbers on WhatsApp and we will confirm it and quote for your area.