The building's water: meters, invisible leaks and runaway bills

The water bill goes up 40% and nobody knows why. Welcome to the classic of invisible leaks.

Finding the ghost leak

1. The still-meter test: one night, with everything closed off (irrigation included), photograph the main meter before and after six to eight hours with no consumption. If it moved, there is a leak.
2. The usual suspects: a leaking cistern in a common room (silent, thousands of litres a month), damaged buried irrigation, garage flush valves, and the main pipe with an underground leak (a stain, low pressure on the upper floors).
3. Professional detection: acoustic listening or tracer gas — the community policy usually covers detection (check the policy), though not always the repair.

Main meter versus individual meters

Where there is a main meter plus individual ones, the difference between the sum of the flats and the main meter is the common water (cleaning, irrigation, pool) plus losses. Watching that difference month by month is the cheapest leak detector there is: when it spikes, something is happening.

Cutting the bill without leaks

• The right tariff and meter size for actual use (oversized meters pay a higher standing charge).
• Irrigation with a timer and a rain sensor (watering in the rain is throwing money away).
• Aerators and dual-flush cisterns in common facilities.

The habit

Note the monthly reading of the main meter (a photo will do) alongside the community's other figures. Two minutes a month that pay for themselves the day something drips where nobody is looking.