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 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.
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
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.
Common questions
Can a tank be too big? Mostly it just costs more up front and takes more space, but very oversized storage can sit long enough that water turnover needs attention. The aim is a sensible buffer, not the largest tank that fits.
Underground or above ground? Both work; it comes down to space, budget and pump setup. The survey is where that gets decided for your property rather than in the abstract.