How to Find a Water Leak in Your Home (Before It Gets Expensive)

Hidden water leaks are one of the most expensive plumbing problems — not because they’re hard to fix, but because they’re often found late. Here’s how to check for a leak yourself before the water bill arrives.

Step 1: Check Your Water Meter

This is the fastest and most reliable leak test you can do yourself.

1. Turn off every tap and appliance that uses water in your home (including the dishwasher, washing machine, and irrigation)
2. Go to your water meter (usually near the front boundary of your property)
3. Note the reading on the dial
4. Wait 15–30 minutes without using any water
5. Check the reading again

If the numbers have moved, you have a leak somewhere. If there’s a small red or blue “leak indicator” dial on the meter face, watch it — if it’s spinning with all taps off, water is flowing somewhere.

Step 2: Test Your Toilets

Running toilet cisterns are one of the most common causes of unexplained water usage. They’re silent, invisible, and waste up to 200 litres per day.

Add a few drops of food colouring to the cistern tank (not the bowl). Wait 10–15 minutes without flushing. If colour appears in the bowl, the cistern is leaking into the bowl.

Step 3: Check All Taps and Valves

Go through every tap in the property including:

• Kitchen and bathroom taps
• Outdoor and garden taps — these are often left dripping for months without anyone noticing
• Under-sink valves (look for moisture or staining under the sink cabinet)
• The connection at the back of the washing machine
• Flexible hoses under sinks and behind toilets — these can fail suddenly and catastrophically

Step 4: Look for Damp Spots

Visible signs of a hidden pipe leak include:

• Dark patches or staining on walls, ceilings, or floors
• Soft, spongy, or hollow sections in timber flooring
• Mould growing in areas not near a shower or bath
• A musty smell in a room with no obvious dampness source
• Wet or very green patches in the garden (can indicate an underground leak)

Step 5: Isolate the Section

If you’ve confirmed a leak but can’t find it, try shutting off individual supply valves (under sinks, behind toilets) one at a time and re-testing the meter each time. This helps narrow down which section of the house the leak is in.

When to Call a Plumber

If your meter test confirms a leak but you can’t find the source, it’s likely an underground or in-wall pipe. These require leak detection equipment and shouldn’t be left. Water tracking inside walls causes mould and structural damage within weeks.

Call Sedcon Plumbing on 0468 013 012 — we carry leak detection equipment and can pinpoint the leak before opening up walls unnecessarily. Related: Burst Pipe Melbourne · High Water Bill Explained.

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