Buying Guide

Water Tank Size Guide: What Capacity Do You Need?

A common rule is 150–200 litres of water storage per person per day. Use that to size your tank, then pick overhead, loft or underground storage.

Sizing a water tank is simple once you know your daily usage. The standard planning figure is about 150–200 litres of storage per person per day. Multiply by the number of people and you have a starting capacity.

Quick sizing chart

HouseholdSuggested tank
1–2 people500 L
3–4 people750–1000 L
5–6 people1000–1500 L
Large family / shared2000 L and up

Add a buffer if your municipal supply is irregular, or if you want a day or two of reserve.

Overhead vs underground

  • Underground / sump tank: stores the incoming municipal supply; a pump lifts it to the overhead tank.
  • Overhead / loft tank: gives gravity pressure to your taps and fixtures.

A typical setup uses both. Where pressure and roof space allow, an overhead tank alone can be enough.

Don't forget the fittings

A tank also needs an inlet, outlet, overflow and (often) a float valve to fill automatically and shut off. We supply all of these.

See water tanks & accessories and Sintex water tanks, or float valves to complete the set-up.

FAQs

What size water tank for a family of 4?

At ~150–200 litres per person per day, a family of four needs roughly 600–800 litres minimum. A 1000-litre overhead tank is a common, comfortable choice that adds a buffer.

How many litres of water does one person use per day?

Indian household usage is commonly estimated at 135–200 litres per person per day across drinking, cooking, bathing, washing and cleaning. Size your tank toward the upper end for comfort.

Should I choose overhead or underground storage?

Many homes use both: an underground/sump tank fed by the municipal supply, and an overhead tank that a pump fills to give gravity pressure to taps. Overhead alone works where supply pressure and roof space allow.

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