# A water reserve at home: a storage tank with a float valve, DIY

> When you need a water reserve, how to size the tank and where to fit the float valve, overflow and pump. A layout for a weak borehole or an unreliable supply.

Web page: https://watertrade.com.ua/en/articles/article/zapas-vody-nakopitelnyj-bak · Other languages: [UA](https://watertrade.com.ua/articles/article/zapas-vody-nakopitelnyj-bak.md), [RU](https://watertrade.com.ua/ru/articles/article/zapas-vody-nakopitelnyj-bak.md)

*September 9, 2026*

![Diagram: house with a storage tank, float valve on the inlet, pump and kitchen tap](https://watertrade.com.ua/uploads/articles/water-storage-tank.jpg)

A storage tank helps when water is scarce or not always available: a low-yield borehole, an unreliable mains supply, water delivered on a schedule. The tank fills slowly, and the house draws water from the reserve at normal pressure.

## What the diagram shows

1 — the float valve on the tank inlet, 2 — the tank itself, 3 — the pump that supplies the house from the tank, 4 — the taps.

## How big a tank

Allow 150–200 L per person per day. A 600–1000 L tank is enough for a family of four for a whole day without any supply. With a weak borehole, size the tank so that it refills overnight.

## Layout and parts

- **Tank** — food-grade, opaque plastic with a lid: water exposed to light grows algae.
- **Float valve** on the inlet stops the water when the tank is full. Above 5 bar supply pressure, choose a diaphragm valve.
- **Overflow** — a pipe 3–5 cm above the working level, routed to the drain or outside.
- **Outlet** — 5–10 cm above the bottom, where sediment settles.
- **Booster set** or a surface pump with a pressure tank to pressurise the house.
- **Drain valve** at the bottom to flush the tank once a year.

## Installation steps

1. Place the tank on a level base in a warm spot — a basement, boiler room or insulated loft.
2. Make the connections: inlet with the float valve at the top, overflow, outlet near the bottom, drain.
3. Connect the booster set to the outlet through a coarse filter.
4. Fill the tank, set the level with the float and check that the overflow works.

> Put a heavy tank in the loft only if the floor can carry it: 1000 L of water weighs a tonne.

Everything for this layout is in our [float valves](https://watertrade.com.ua/en/catalogue/krany-poplavkovye) and [pressure tanks](https://watertrade.com.ua/en/catalogue/gidroakkumulatory) sections.

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