A dripping tap seems louder overnight because water pressure in household pipes rises when neighbourhood demand falls, and that extra pressure pushes past a worn washer or seal that was holding firm during the day. The quickest fix tonight is to relieve that pressure: open a nearby tap slightly or isolate the fixture at its valve. If the drip keeps coming back, or more than one tap is affected, it is time to book a plumber rather than keep patching the symptom.
TL;DR:
- Most household taps in Australia that drip at night are caused by higher overnight pressure or thermal expansion, not a single faulty part.
- If a drip persists after replacing the washer or cartridge, pressure issues or worn valve seats are likely the underlying cause.
- Checking whether multiple taps drip or just one helps determine if the problem is local or systemic, guiding appropriate repairs or pressure tests.
- Relieving pressure by opening another tap slightly can stop overnight drips temporarily and prevent flooding when fixing the issue.
- Calling a licensed plumber is advisable if multiple fixtures leak or if there are signs of corrosion, significant pressure fluctuations, or persistent leaks after DIY efforts.
Table of Contents
- Quick temporary fixes to stop the dripping noise tonight
- Why taps can drip only at night: pressure, thermal expansion and perception
- How to diagnose the cause: quick tests to run and what results mean
- How to fix common dripping taps yourself (step-by-step for compression, cartridge and mixer taps)
- When to call a plumber and what a licensed plumber will check
- A plumber’s quick note on realistic expectations
- If you prefer a professional: how Priority Plus Plumbing can help
- Sources
- FAQ
Quick temporary fixes to stop the dripping noise tonight
You do not need to solve the whole problem at 11pm. You just need it quiet enough to sleep, without causing a bigger mess by morning.
Draping a face towel or a folded chux over the tap outlet muffles the plink without blocking drainage, though swap it out the next day so it does not turn into a damp, mouldy nuisance. A better trick, and one plumbers actually use, is to open a tap elsewhere in the house a fraction. That bleeds off some of the built-up pressure in the line and often slows the drip immediately.
- Muffle the sound with a towel or sponge under the drip, changed the next morning.
- Crack open another tap slightly to relieve line pressure.
- Crack open another tap slightly to relieve line pressure.
- Turn off the isolation valve under the sink if the tap has one, stopping the leak entirely overnight.
- Shut the house mains only if you cannot find an isolation valve or suspect a burst, and know where that valve is before you need it in the dark.
Pro Tip: Keep a small torch and your mains tap location written on the inside of a cupboard door. Fumbling for the shutoff at 2am with your phone torch is how minor drips turn into midnight floods.
Why taps can drip only at night: pressure, thermal expansion and perception
Councils supply water at higher pressure overnight because far fewer households are running taps, showers, and irrigation systems at 2am. That pressure rise is often enough to push water past a washer or O-ring that seals adequately under daytime pressure but not under the overnight spike. Add a hot water system heating overnight, and the resulting thermal expansion can push pressure higher still in a closed system, forcing a few extra millilitres through the weakest point in your plumbing.
- Reduced demand overnight raises street-main pressure across most suburbs.
- Hot water systems reheating overnight expand water volume, adding pressure in closed loops.
- Ambient household noise drops to near zero after midnight, so a drip that was inaudible over daytime traffic and appliances becomes obvious.
- A tap that seems fine by day can still be marginal enough to fail only under night pressure.
Cambridge engineering research explains that the sound itself is largely acoustic. The familiar plink comes from a pocket of trapped air oscillating as the droplet hits the water below, which is why a single drop sounds so disproportionately loud in a quiet house. That matters practically: replacing the tap itself will not help if the real driver is house-wide pressure behaviour rather than a fault confined to that one fixture.
How to diagnose the cause: quick tests to run and what results mean
Before you pull a tap apart, spend ten minutes working out whether the problem is local or systemic. It saves you buying the wrong parts twice.
- Unscrew the aerator and listen close to the spout. If the drip sound disappears or changes character, scale build-up in the aerator was likely amplifying it.
- Check whether only one tap is dripping or several. One fixture points to a worn washer or cartridge; multiple fixtures dripping at once points to a system-wide pressure issue.
- Attach a hose-bib pressure gauge to an outdoor tap and take a reading at 9pm and again at 2am. A jump of more than 10 to 15 PSI overnight suggests your pressure-reducing valve isn’t holding steady, which is the systemic explanation rather than a single bad seal.
- Open another tap in the house while the dripping one runs. If the drip slows noticeably, pressure in the line is a major factor, not just wear.
Pro Tip: Run the pressure gauge test twice, a week apart, before assuming it is a one-off. Pressure can spike after mains maintenance work in your street and settle back down on its own.
How to fix common dripping taps yourself (step-by-step for compression, cartridge and mixer taps)
Most household taps in Australia fall into one of three types, and each has a slightly different fix. Shut off the isolation valve under the sink first, plug the drain so you do not lose small parts, and work on a towel so you can see everything laid out in order.
Compression (washer) taps, the classic two-handle style with separate hot and cold:
- Remove the decorative cap and unscrew the handle.
- Use a spanner to remove the tap body, exposing the washer at the base.
- Replace the rubber washer, checking the brass seat underneath for scoring or corrosion.
- Reassemble and turn the isolation valve back on slowly, checking for drips at the spout and around the handle.
Cartridge and mixer taps, the common single or dual-lever type:
- Prise off the decorative cap and remove the retaining screw underneath.
- Lift out the cartridge, noting scale build-up or a cracked O-ring.
- Clean the cartridge in a vinegar solution or replace it outright if the seals are visibly worn.
- Reassemble in reverse order and test the lever’s full range of motion.
Worn washers, damaged O-rings, corroded valve seats, and failed ceramic cartridges account for the majority of household tap leaks in Australian plumbing systems. While you are in there, unscrew the aerator and soak it in vinegar to dissolve scale, since a clogged aerator often gets mistaken for a worn cartridge.
- Never overtighten the handle to “force” a stop. It strips the mechanism and makes the next repair harder.
- Test overnight before calling the job done. A drip that seems fixed at 6pm can reappear once pressure climbs at midnight.
Pro Tip: If you’re not confident isolating the water supply safely, our step-by-step tap repair guide walks through the process in more detail before you start.
When to call a plumber and what a licensed plumber will check
Some situations are not a weekend DIY job, and pretending otherwise usually costs more later.
Call a licensed plumber if more than one tap drips at night, you notice greenish corrosion around fittings, water pressure swings wildly through the day, or you spot damp patches or water staining near a fixture. A plumber will test incoming mains pressure, check whether your pressure-reducing valve is holding its set point, inspect for thermal expansion issues in the hot water system, and examine valve seats and cartridges for wear beyond a simple washer swap.
- Multiple leaking taps or fittings across the house
- Visible corrosion, staining, or water damage near a tap
- Pressure that fluctuates noticeably between day and night
- A drip that returns within weeks of a DIY repair
These jobs are typically diagnosed with upfront pricing before work starts, backed by a workmanship guarantee, so you know the cost and the fix before anything is touched.
A plumber’s quick note on realistic expectations
Peter Honey here. On most first visits, a genuine washer or cartridge fault gets sorted within the hour. If the drip keeps coming back after that, the pressure system, not the tap, is usually the real culprit. Some plumbing services offer 24/7 emergency response with upfront pricing and a workmanship guarantee, so there are no surprises either way.
— Peter Honey
If you prefer a professional: how Priority Plus Plumbing can help
A DIY washer swap fixes plenty of drips, but a pressure-related fault will keep returning no matter how many times you replace the same part. A professional plumber can test incoming mains pressure, check whether the pressure reducing valve is holding correctly, and inspect for thermal expansion problems in the hot water system before touching the tap itself, so the fix actually holds.
Some plumbing services offer upfront pricing agreed before work starts and a workmanship guarantee, with teams available on call 24/7 for anything from a single stubborn tap to a full pressure diagnosis. If a leaking tap has you second-guessing whether it is urgent, our page on what counts as a real plumbing emergency explains where a dripping tap sits on that scale. If pressure or hot water system issues turn out to be the culprit, our hot water repair specialists can trace the fault back to its source. Book a diagnosis online and get a straight answer on cost before anyone picks up a spanner.
Sources
The Cambridge engineering explainer covers the acoustics behind the sound itself. The RACV repair guide offers practical, Australia-specific repair steps. YourHome’s water guidance covers why fixing small leaks saves meaningful water over time.
- What causes the sound of a dripping tap — and how do you stop it? | Engineering (University of Cambridge)
- How to fix a dripping tap: step-by-step guide for Australian homes | RACV
FAQ
Should I worry about a dripping tap?
A single dripping tap is rarely dangerous, but it wastes water continuously and often signals a worn part that will get worse. Left long enough, some drips also stain fixtures or feed mould around the tap base.
What are the common causes of dripping taps?
Worn rubber washers, damaged O-rings, corroded valve seats, and failed ceramic cartridges cause most household tap leaks. Overnight pressure rises and thermal expansion in hot water systems can turn a marginal seal into an active drip.
Why is my faucet dripping even though the valves are closed?
If the isolation valve is fully closed and the tap still drips, the valve itself may be worn or not seating properly, or residual pressure in the line is bleeding through a failing cartridge downstream. This usually points to a plumber-level fix rather than a simple washer swap.
Why is my kitchen tap dripping when the water is off?
This typically means the cartridge or washer inside the tap body has failed and is no longer sealing fully, letting mains pressure push water through even with the handle in the off position. It is one of the clearest signs a repair is overdue rather than optional.