Water Watch

What actually helps, if you have a cistern

Most of the water a household loses in a drought is not water it chose to use. It leaves through a fitting nobody has looked at in years, or it never reaches the tank in the first place. These are the checks worth doing this week, roughly in the order they pay off.

Read the tank when nobody is using water.

Note the level last thing at night and again before anyone is up. If it is lower by morning, the cistern is losing water — and it is losing it all day too, where ordinary household draw hides it. This single check is what separates “we use a lot” from “we have a leak”, and it costs nothing but two glances.

The most expensive leak makes no noise.

A toilet flapper that no longer seats passes roughly 30 gallons a day in complete silence — around 20% of everything a typical household here gets through. Put a few drops of food colouring in the tank, leave it fifteen minutes, then look in the bowl. Colour in the bowl means the flapper is passing, and it has probably been passing for months.

Listen to the pump.

A pressure pump that starts up while every tap in the house is closed is replacing water escaping somewhere past it. Unlike a dripping tap, that somewhere is usually under a slab, behind a wall, or in a buried line — which is exactly why it runs so long before anyone finds it.

Fix the catchment before the rain, not after.

Only 4 spells of rain in our whole record have been heavy enough to register across the territory. When rain is scarce, a blocked gutter or a first-flush diverter stuck shut does not cost you a little water — it costs you a whole event. Clear the gutters and downpipes, check the screens, and confirm the diverter actually drains and resets between showers.

Know your own number.

About 151 gallons a day is the middle of the monitored fleet. A household well above that, with the same number of people, is usually looking at irrigation, a pool or a cistern top-up, or a leak — in that order of size, and in the reverse order of how visible they are.

What is at stake is easy to underrate. The last significant rain put about 43 gallons into the average monitored cistern, less than a day of ordinary household use. A silent 30-gallon-a-day leak gets through the same volume in 1 day, and it does that whether or not it rains.

A leak is only cheap to fix while it is still small, and the ones that matter are the ones nobody can see. Continuous monitoring is how they get caught — it watches the level around the clock and raises an alert when a tank falls in a way normal use does not explain. How leak detection works.

How to read these numbers

This measures water captured, not rainfall.

A cistern records what its roof delivered into it. Roof area, gutter condition and first-flush diverters all vary between properties, so this is a measure of harvested water — closely tied to rainfall, but not the same quantity as inches on a gauge.

The decline is at least this steep, not exactly this steep.

The headline compares all water entering cisterns, trucked deliveries included. Deliveries rise during a drought, which holds that number up. We separate the ones we can identify by their signature — a large volume arriving within an hour or two — but the separation is a rule of thumb, not a receipt.

Our record is short, so we make no historical claim.

This series is a little over three months long, and the monitored fleet grew several-fold inside that window. We cannot compare this drought to last year or to any past dry season, and nothing here should be read as “the worst since” anything.

Monitored cisterns are not a random sample.

They belong to households and businesses that chose to install monitoring. That is not a cross-section of the territory, and the fleet is concentrated wherever our customers are rather than spread evenly across it.