A sudden jump in your water bill is almost always a sign of an undetected leak somewhere on the property. Normal household water consumption is reasonably stable over time, a sudden 50-200% increase from one bill to the next means water is going somewhere it should not. Find the source, fix it, the bill returns to normal.
The fastest diagnostic test
Read your water meter, wait 30 minutes with no water use anywhere in the house (no taps, no toilets flushing, no dishwasher, no irrigation, no pool top-up), then read the meter again. If the reading has changed, you have a leak. If the meter has not moved, your bill increase is from genuine use (more occupants, more usage, hotter weather increasing garden / pool consumption).
Most modern meters have a small "leak indicator" (a tiny dial or star that spins when water is flowing). If the leak indicator is moving with everything off, there is definitely a leak.
The common leak sources, ranked by frequency
1. Toilet running constantly (most common)
A toilet with a failed flush valve seal or inlet valve can run constantly without you noticing (slow trickle into the bowl rather than a full flush). Wastes 200-400 L per day, $80-180 per year on Gold Coast water rates. Diagnostic, add food colouring to the cistern, wait 30 minutes without flushing, if colour appears in the bowl, the flush valve is leaking. Repair $160-280.
2. Dripping outdoor tap
Often overlooked because outdoor taps are out of mind. A single dripping tap can waste 20-50 L per day. Garden hose taps left slightly on are common. Walk the property checking every outdoor tap. Replacement $160-280 each.
3. Slow leak at a fitting
Under-sink fittings, behind-toilet connections, behind-dishwasher connections all can develop slow drips that go unnoticed. Check under every sink and behind every appliance for damp or water stains. Repair varies by location.
4. Irrigation main burst
Underground irrigation lines damaged by ground movement, root pressure, or landscaping. Symptoms include soggy patches in the lawn, reduced pressure at sprinklers, jump in water bill. Locate and repair, $360-720.
5. Swimming pool leak
Pool leaks can be significant (50-500+ L per day depending on size). Check water level with a marker, compare after 24 hours allowing for normal evaporation (5-10 mm per day in summer). Significant additional loss = leak. Pool repair is specialist work.
6. Hidden in-wall or under-slab pipe leak
The worst kind of leak. Water leaks into wall cavity or sub-slab space without visible symptoms until significant damage has occurred. Symptoms eventually include damp patches on walls / ceilings, increased water bill, hot water unit running constantly (if leak is on hot line), sound of running water with everything off. Requires plumber to locate and repair.
7. Pool top-up auto-fill stuck open
For canal-front and other pool homes with auto-fill, a stuck valve allows continuous water flow into the pool. Pool overflows. Easy fix once on-site, $260-460.
8. Acreage tank-water pump leak
For acreage on tank water, a leak between the pump and the dwelling, or in the pump pressure tank itself, manifests as constant pump cycling. Diagnose and repair.
What we do to find a leak
- Check the meter to confirm a leak exists.
- Walk the property checking visible plumbing for drips, damp, stains.
- Test toilets, taps, appliances systematically.
- Isolate sections of the supply system if needed to narrow down the location.
- Use acoustic leak detection for buried or hidden leaks (specialised equipment that picks up the sound of water escape).
- Use thermal imaging for in-wall hot water leaks (the warm patch shows on the wall).
- Trace pipes to locate suspected leak point.
- Expose and repair.
Cost to find and repair
- Simple visible leak (dripping tap, running toilet): $180-400
- Slow leak at accessible fitting: $260-480
- Buried external pipe leak (excavate and repair): $400-1,200
- In-wall or sub-slab leak (locate + expose + repair + reinstate): $600-2,500
- Pool leak diagnosis (pool specialist): $400-1,000
- Acoustic leak detection service: $300-600 for a thorough survey
How much can a small leak cost over time
- Single dripping tap (20 L/day): $30-50 per year, plus the noise
- Constantly running toilet (200-400 L/day): $80-180 per year
- Slow under-slab leak (50-100 L/day): $50-130 per year, plus eventual major damage
- Hot water in-wall leak (varies): water loss + HWU running constantly + eventual wall damage easily $500-2,000 per year
- Irrigation main burst (500-1,000 L/day): $300-600 per year just in water
What to do
If your water bill has jumped suddenly, do the meter test today. If the meter is moving with everything off, call us. Most leaks can be located and repaired in a single visit, $200-1,200 typical depending on cause. Investment pays itself back within a year in reduced water bills, plus prevents the eventual damage from progressing leaks.
Reading the meter properly, the bit nobody explains
The single most useful skill for any homeowner is reading the water meter correctly, but the meters Gold Coast City Council installs vary by suburb and vintage and the readings can be confusing. The standard modern meter has a digital LCD display showing total consumption in kilolitres to 3 decimal places (so 0.001 kL = 1 L), plus a small mechanical leak detection dial (often a star or triangle shape) that spins continuously if water is flowing. The older mechanical meters have rotating number wheels and a single small red triangle or star as the leak indicator. To do a proper leak test, turn off every internal and external water use (taps closed, toilets not flushing, dishwasher and washing machine not running, irrigation off, pool top-up off), wait 5 minutes for any cistern fills to complete, then watch the leak indicator for 60 seconds. Any movement at all means water is flowing somewhere, even slowly. Then note the LCD reading to 3 decimal places, wait 30 minutes without using anything, and read again. Subtract to get the leak rate in litres per 30 minutes. Multiply by 48 to get litres per day. A leak of 5 L per 30 minutes (small enough to be invisible to the naked eye) is 240 L per day, or $80 to $130 per year on Gold Coast water rates. We get calls from owners insisting they have no leak because the meter looks unchanged, but they have not used the leak indicator and they have not waited long enough between readings to see the slow drift. Send us a photo of your meter through the WhatsApp number on our website and we can walk you through the reading remotely, free service for any concerned owner before they commit to a paid callout.
The seasonal pattern in Gold Coast water bills
Some sudden-bill-jumps are not leaks, they are seasonal usage patterns that the owner has not connected to their billing cycle. Gold Coast City Council bills quarterly, and the worst bill is usually the one covering January through March, peak summer with maximum garden watering, pool top-up, hot weather showering, and visitors over the school holidays. A typical Robina or Burleigh family that uses 130 kL per year averages roughly 32 kL per quarter, but the summer quarter can be 45 to 60 kL and the winter quarter as low as 18 to 22 kL. If you have just moved into a new property, your first summer bill can be a genuine shock compared to your previous home if the new property has a pool, larger gardens, or different occupancy patterns. Before assuming a leak, check the previous owner's bills (the agent can sometimes provide these) or check your meter readings over a 7 to 14 day period to estimate daily consumption and project annual usage. Normal Gold Coast household usage is roughly 100 to 200 kL per year for 2 to 4 people without pool or extensive gardens, 200 to 350 kL with pool, 300 to 500 kL with pool plus extensive gardens or canal-front lawn irrigation. If your projected annual usage is in the normal range for your property type, the bill is normal not leaking. If the projection is 50%+ above the normal range, leak investigation is warranted. We can do a 10 minute phone consultation to help you triangulate before booking a service call.
Hot water unit running constantly, the hidden leak indicator
A leak on the hot water supply line (between the HWU and a fixture or appliance) shows up two ways, on the water bill as increased consumption, and on the gas or electricity bill as increased HWU run time. We had a client in Mudgeeraba in 2024 whose gas bill jumped $180 in a quarter with no apparent reason, the leak was a slow drip on a copper joint behind the wall feeding the master ensuite, dripping into the wall cavity and out into the slab. The hot water unit was reheating the lost water continuously, doubling the gas consumption, and the water meter was barely showing the loss because the drip rate was low. The first symptom the owner noticed was actually the gas bill, not the water bill. If you have an unexplained increase in HWU run time, the burner cycling more often, the pilot light visible more often, or for heat pump owners the compressor running outside its normal duty cycle, suspect a hot water side leak. Touch the cold water inlet pipe on the HWU after a period of no use, it should be at ambient temperature, if it is warm or hot the unit has been running recently which means water is flowing somewhere. Inspect under-sink hot supply connections, behind-toilet supplies (some toilets have warm water connections), washing machine hot tap, dishwasher hot supply, and the HWU itself for any moisture or staining. Hot water leaks cost more than cold water leaks because you pay for the water and the energy to heat it, the financial damage compounds quickly. We use a calibrated infrared thermometer on suspected pipe runs to find warm spots indicating hidden hot water leaks, $180 to $260 callout for a typical suburban investigation.
What council does and does not allow for high-bill complaints
Gold Coast City Council has a high-bill review process that owners can use when they believe their bill is incorrect, but the criteria are narrow and most leak-related high bills do not qualify for adjustment. Council will consider a bill review when there is evidence of a meter fault (rare but possible), incorrect meter reading (usually estimated readings during access issues), or a hidden underground supply leak between the water meter and the dwelling (this is council infrastructure responsibility up to the meter, owner responsibility downstream from the meter). A burst pipe inside the house or on visible plumbing is owner responsibility and council will not adjust the bill, even if the leak is documented and the repair has been done. The exception is a single rebate available once per property for a hidden internal leak, where if you can document the leak repair (plumber invoice, location of leak, repair date) council may consider a one-off partial rebate. Apply within 90 days of repair via the Gold Coast City Council water services portal. The rebate is typically 50% of the additional water cost above your normal consumption for that quarter, not the full amount. Worth applying if you have a properly documented repair, not worth applying for visible-fixture leaks (dripping taps, running toilets) that should have been caught and fixed earlier. We provide a leak repair invoice with location, date and description specifically designed to support council rebate applications, so owners who use us for the repair have the documentation in the format council wants. Small detail, modest payback, but worth doing.