Shocked by Your SA Water Bill? The 15 Minute Test That Finds the Leak

Read the bill properly before you read the meter

SA Water bills quarterly, and water use is measured in kilolitres. A kilolitre is 1,000 litres, which is why a number that looks small on the page can represent a great deal of water. Before assuming a leak, spend 10 minutes with the bill itself, because a meaningful share of shock bills are not leaks at all.

• Check whether the read is actual or estimated. An estimated read is followed by a catch-up when the next actual read happens, so a spike can be a correction to earlier under-billing rather than new usage.
• Compare against the same quarter last year, not against last quarter. The December to February period is the highest of the year for almost every Adelaide household with a garden, and comparing summer against spring proves nothing.
• Water use is charged in tiers, so the extra kilolitres a leak produces are billed at the highest tier you reach rather than at the base rate. A leak of constant size costs more per litre the longer it runs.
• Look at the fixed supply charges separately from the usage charges. A bill can rise without a single extra litre being used.
• Match the read printed on the bill against the digits on the meter face today. If those cannot be reconciled, raise it with SA Water on the account number printed on the bill before spending anything on plumbing.

Only once the bill itself has been ruled out does the meter test become the next step. Doing it in that order costs nothing and regularly ends the investigation on the first afternoon.

The 15 minute meter test

This is the test that decides everything that follows. It requires no tools and no tradesperson, and its result determines whether spending money on leak detection is sensible or pointless.

1. Turn off every tap inside and outside the house. Stop the washing machine and the dishwasher. Do not flush a toilet during the test.
2. Switch off the irrigation controller at the wall rather than pausing the current program.
3. Find the meter, which in metropolitan Adelaide is normally at the front boundary. Photograph the whole face, including the small red dials, with the time visible on your phone.
4. Leave everything alone for 15 minutes.
5. Photograph the meter again and compare. Any movement in the red dials means water is passing the meter with nothing in use.

If the meter moves, do the test a second time with the stop tap at the house closed. Movement with the house isolated puts the leak in the buried service run between the meter and the house. No movement with the house isolated puts it inside. That single extra step halves the search area before anyone is paid to look at anything.

Turning the movement into a number

Meter movement on its own is only half the answer. Converting it into litres per day is what tells you whether this is a small part to replace or a driveway coming up, and it explains a bill that otherwise looks impossible.

That table is the reason a leak nobody can hear produces a bill nobody expected. A weep too quiet to notice standing next to it runs 24 hours a day for the entire 91 days of the billing period, and it never takes a day off. Household usage that feels dramatic by comparison, a long shower or an extra load of washing, is trivial next to a constant loss.

Where Adelaide leaks actually hide

Hidden leaks are not evenly distributed. The same handful of faults account for most of them, and they are worth checking in this order because that is roughly the order of how often they turn out to be the answer.

The toilet cistern comes first, and it fails in 2 different ways. The obvious one is the outlet valve seal weeping into the pan, which a dye test finds: a few drops of food colouring into the cistern, do not flush, come back in 20 minutes, and colour in the pan confirms it. The second way is the one that gets missed. When the inlet valve is set too high or fails to shut off cleanly, water trickles continuously down the cistern's internal overflow tube straight into the pan. There is nothing to see in the bowl, nothing to hear in the room, and it can run for a year.

Hot water relief valves come next. A storage system has valves designed to discharge, and the discharge line usually runs to the ground beside the unit or into the stormwater where nobody looks at it. Occasional discharge is normal. Continuous discharge is a fault, and it almost always points to either a failed expansion control valve or mains pressure above what the system is rated for. AS/NZS 3500 limits static pressure at any outlet to 500 kPa, and a pressure limiting valve at the meter fixes the discharge, protects the cylinder and extends the life of every tap in the house at the same time.

• Irrigation solenoids: grit under the diaphragm makes a valve weep permanently. Check for a controller program nobody set, and for drip line damaged by a whipper snipper or a dog.
• The buried service run: copper or polyethylene between the meter and the house, frequently under a driveway. In reactive clay the water tracks along the trench, so the damp patch or the unusually green stripe in February is often metres from the actual break.
• Flexible hoses under vanities and kitchen sinks: they fail by bursting rather than weeping, but a slow seep at the crimp will run into a cupboard base for months.
• Forgotten lines: a shed, a garden tap behind a retaining wall, an old trough, a stock line on a hills property. Plenty of properties have supply nobody has thought about in 20 years.

When you do not have a leak at all

If the meter does not move with everything off, you do not have a leak. Nothing on the property is losing water while nothing is running, so there is nothing for anyone to find and leak detection is not the next step. This is the most useful sentence on the page, because a large share of shock bills have an explanation that costs nothing to confirm.

• Seasonality. The December to February quarter is the highest of the year for nearly every Adelaide household that waters a garden.
• Estimated reads catching up. Estimates that ran low for 2 quarters, followed by an actual read, produce a bill that looks exactly like a leak and is not one.
• More people in the house, or people home more of the day.
• A new lawn, a new garden or new plantings, all of which drink far more in their establishment season than they ever will again.
• A first summer with evaporative cooling. That unit uses real water by design, and the bill reflects it honestly.
• A pool or spa topped up through a heatwave, where evaporation alone accounts for a surprising volume.
• A change in tariff or fixed supply charges, which raises the total with no change in litres at all.

Where the bill still cannot be reconciled and you and SA Water cannot reach agreement, the Energy and Water Ombudsman SA handles disputes between customers and water retailers at no cost to the customer. That is the right escalation path, and it is worth knowing about before frustration turns into simply paying an amount you believe is wrong.

What professional leak detection actually does

Leak detection on a supply line is a process of elimination rather than a single instrument. The property is split into sections at the taps that already exist, each section is put under pressure and watched, and the section that loses pressure is the one holding the leak. It is worth being straight about the limit of that: isolation narrows a loss to a length of pipe, not to a single tile, and the last step is opening up the section that failed. What it buys you is that the ground which gets opened up is the ground the leak is actually under.

• The meter test and the leak indicator dial: everything off, watch the dial, and run it overnight where the loss is too small to read confidently over 15 minutes.
• The stop tap where the service enters the building: close it, then watch the meter. A meter that keeps moving puts the loss out in the buried run before that point, and a meter that stops puts it inside. That is the single biggest cut in the search area available.
• The cold inlet valve at the hot water unit: closing it separates the hot circuit from the cold, and a meter that stops there puts the loss in the hot run, usually under a slab or a floor.
• Ruling out the fixtures first: cisterns passing into the pan, mixer cartridges, flexible hoses, a relief valve discharging, an irrigation solenoid weeping, an evaporative cooler dumping. These account for most internal losses, and none of them need equipment to find.
• Section by section pressure testing: isolate a line, bring it up on a gauge, and watch for decay. A section that holds its pressure is ruled out, and a section that falls away is the one to open up.
• Thermal imaging over the section that failed: the camera reads surface temperature, it does not see through a slab or a wall. What it picks up is heat that a leak has carried up to the surface, or an area that has gone cool because water is evaporating out of it. That makes it strong on a hot water line under a slab and close to useless on a cold water pinhole with no temperature difference around it.
• A moisture meter across floors, skirting and wall linings: it measures moisture in the material rather than locating the pipe, so it maps how far the water has tracked and tells a wall that is wet now from a stain that dried out months ago.
• CCTV drain inspection: for drainage faults, which are a different problem entirely. A cracked sewer does not register on a water meter, because the water passing through it has already been billed.

Thermal imaging and the moisture meter change the size of the hole only when the leak gives them something to read. A hot water line under a slab usually does, because the warm plume comes through the floor and the moisture map around it shows where the wet material stops, so what gets opened up is a small area of floor rather than a run. A cold line with no temperature contrast does not, and there the honest answer stays what it was: isolation and section pressure testing hand you a section, and the section is what gets opened.

Attendance and staged isolation are often all an internal leak needs, because between them they identify the fixture and the repair in the same visit. What extends a job is depth and reinstatement: a buried service line under a driveway has to be exposed and the surface put back, and that is decided by the property rather than by the leak.

Who pays: the meter is the boundary

In South Australia the water meter is the line of responsibility. SA Water owns and maintains the main in the street and the meter itself. Everything on the property side of that meter belongs to the owner, including the buried service run up to the house. That single fact decides who pays for a repair, so establishing which side a leak sits on comes before anything else.

• Water surfacing on the street side of the meter, or the meter pit itself full of water, is SA Water's to investigate. Report it to them rather than calling a plumber.
• Anything past the meter, including the line under your own driveway, is the property owner's cost.
• On the sewer side, the private sanitary drain within the property is the owner's responsibility and the sewer main is SA Water's.
• Units and townhouses on a shared meter are a special case: a single dwelling's leak lands on everyone's account, and finding it means isolating dwelling by dwelling rather than testing the common meter.

For a rental property, we are plumbers rather than tenancy advisors, so treat this as practical guidance and check the detail with Consumer and Business Services or your own advisor. What we can say from experience is that reporting a suspected leak to the agent in writing, with the date and a photograph of the meter, removes almost every argument that follows. Delay is what turns a straightforward repair into a dispute about who knew what and when.

Questions we get asked

References

• SA Water: water bills, meter reads and reporting a leak
• Energy and Water Ombudsman SA: free dispute resolution for water customers
• WELS water rating scheme: fixture and appliance water efficiency