A small leak can hide for months. A cistern that trickles into the bowl or a pipe that weeps inside a wall rarely makes much noise. The first sign is often a water bill that seems higher than it should be. By then a lot of water may already have gone down the drain.
The good news is that most leaks are easy to find with a few simple checks. Some are a quick fix with a new washer. Others need a licensed plumber. This guide walks through where leaks hide and what to look for.
Why small leaks matter
A drip does not look like much. The Australian Government’s Your Home guide says a tap leaking at one drip a second wastes more than 12,000 litres of water a year. That is water you pay for and never use. Over several taps and several years, it adds up.
Toilets can waste even more. Your Home says a slow, barely visible toilet leak can waste more than 4,000 litres a year. A visible, constant leak can waste more than 96,000 litres. These leaks are easy to miss because the water slips quietly into the bowl.
Leaks also cause damage. Water escaping inside walls, under floors or beneath paving can lead to rot, staining and mould. It can also lift tiles and swell timber. Finding a leak early usually means a smaller repair bill.
Start with the water meter
The meter is a simple place to begin. Turn off every tap and appliance that uses water in the house and garden. Make sure the washing machine, dishwasher and irrigation are not running. Then take a photo of the meter reading or note down the numbers.
Wait an hour or two without using any water. Read the meter again. If the numbers have moved, water is going somewhere. Sydney Water notes that the bigger the change, the bigger the potential leak.
Leave the tap at the meter turned on during the test. Sydney Water says the meter tap needs to stay on for the check to work. If the numbers move but you cannot find the leak, a licensed plumber can help track it down.
The toilet dye test
Toilets are one of the most common sources of hidden leaks. Your Home suggests a simple test. Put a couple of drops of food colouring or dye into the cistern. Do not flush.
Wait about 15 minutes and look in the bowl. According to Your Home, if colour appears in the bowl within that time without flushing, there is a leak. It means water is getting past the seal at the bottom of the cistern. The toilet should then be repaired.
A worn seal or a faulty inlet valve is often the cause. These parts wear out with age. In most states, work on household plumbing needs a licensed plumber. Check the rules where you live before taking anything apart.
Dripping taps and showers
Taps are easier to spot because you can see the drip. Check kitchen, bathroom and laundry taps, plus the outside garden taps. Look at the shower head too after it has been turned off for a while. A steady drip is a sign that something inside has worn.
Your Home advises fixing leaks straight away. It also warns against turning taps off too hard, because this can wear the washer and cause leaks. Many people overtighten a dripping tap to stop it, which only makes the problem worse. A gentle turn is all a healthy tap needs.
If you are replacing tapware, it is worth checking the WELS star rating. Your Home explains that the national Water Efficiency Labelling and Standards scheme rates the water efficiency of products such as taps, showers and toilets. A higher star rating means a more water efficient product.
Leaks you cannot see
Some leaks hide behind walls or under the ground. Signs inside the house include damp patches, bubbling paint, musty smells or skirting boards that look swollen. Floors that feel soft or tiles that sound hollow can also point to water underneath. A plumber can trace the source with the right equipment.
Timber is especially vulnerable to water. Floors, decks and cabinetry can warp, swell or rot if they stay damp. Our guide to choosing the right timber explains how different timbers handle moisture. Choosing well helps, but no timber likes a slow leak.
Outside, look for patches of lawn that stay green and soggy when the rest of the garden is dry. Water bubbling up between pavers is another sign. Sometimes a leak shows as a sinking spot in the garden bed. Our article on comparing soil types explains why some soils drain fast and others hold water.
Hot water systems and appliances
Check around the hot water system as well. Your Home notes that storage water heaters release some water through a pressure release valve when they are heating. So a small discharge while it heats is expected. Your Home also suggests having a professional check the release valves on your water heater.
Look under the kitchen and bathroom sinks with a torch. Check the hoses behind the washing machine and the dishwasher connection. Rubber hoses can perish with age and split without warning. Replacing old hoses is a cheap job that can prevent a flood.
Regular checks pay off for any equipment in the home. Our tips on residential lift care show how regular maintenance keeps faults to a minimum. The same habit works for plumbing. A quick look every few months can save a lot of trouble.
When to call a plumber
Some fixes are simple. Others need a licensed professional. Rules about what a homeowner can do themselves differ between states and territories. When in doubt, call a licensed plumber.
A plumber is the right call for leaks inside walls, under slabs or in the pipe from the meter. The same goes for hot water systems and anything connected to gas. Ask about the fault, the likely cause and the cost before work starts. Keep the invoice in case the problem comes back.
Finding a good tradie can take some time. Ask friends and neighbours who they trust, and check the licence before you book. Our article on building industry connections looks at how good trades find each other. Those same networks can point you to a reliable plumber.
Frequently asked questions
How do I check my house for a water leak?
Turn off every tap and appliance, then note the reading on your water meter. Wait an hour or two without using water and read it again. If the numbers have moved, there is likely a leak somewhere.
How do I tell if my toilet is leaking?
Add a couple of drops of food colouring to the cistern and do not flush. Your Home says that if colour shows in the bowl within 15 minutes, the toilet has a leak. It should then be repaired.
How much water does a dripping tap waste?
Your Home says a tap dripping once a second wastes more than 12,000 litres a year. Fixing the drip quickly saves water and money. Avoid overtightening taps, as this wears the washer.
Can I fix a leak myself?
Simple jobs like replacing a washing machine hose may be fine. Most work on household plumbing needs a licensed plumber, and the rules differ between states. Check with your local plumbing regulator if you are unsure.
You can read more about leaks, toilets and taps in the Your Home guide to reducing water demand from the Australian Government.