What size water tank does a villa on Koh Samui need?

A storage tank does one job: it bridges the gap between when water arrives and when you use it — a slow well overnight, a delivery that's a day late, a dry-season pressure drop. Size it for the realistic gap, not the best case, and dry season stops being a crisis. The small pressurised vessel next to the pump is a different machine with its own sizing rules.

The sizing logic

Occupants × daily use × the number of days you want to cover. A four-person villa with a pool and garden on Samui commonly lands around 3,000–5,000 litres; a small resort is a different calculation entirely. These are planning figures — your real number comes from your actual occupancy and how you're supplied. A large garden changes the sum; irrigation demand from a well is worked out separately.

Material and placement matter too

• Material — PE, fibreglass and stainless each trade off cost, lifespan and where they suit
• The base — a tank on a poor base is a slow-motion failure; it needs level, solid ground
• Access — where the tank can physically go, and how the truck or pipe run reaches it

Litres are only the first decision. Whether you need a raw and a treated tank, how several tanks should be joined, and how the inlet, overflow and draw-off should be arranged is in villa water storage done properly.

None of this is guesswork on site: the free survey checks the base, the pipe runs and the access before anything is ordered, so the tank you buy is the tank that fits.