Your Melbourne Water Bill Jumped: How to Find a Hidden Leak

Quick answer: Turn off every tap and water-using appliance, then read the black and red digits on your water meter. Wait 30 minutes without using any water and read it again. If the numbers moved, you have a leak. Once a licensed plumber repairs it, your retailer may credit part of the excess usage under a hidden leak allowance.

A Melbourne water bill arrives quarterly, which is exactly long enough for a small underground leak to turn into an unpleasant surprise. I get these calls most often from Baxter and the larger blocks out that way, where a leak in a long pipe run can sit unnoticed for a full billing cycle.

First, work out which retailer you are with

Melbourne has three water retailers, split geographically:

• South East Water — most of the south-east: Casey, Greater Dandenong, Monash, Kingston, Frankston, Mornington Peninsula
• Yarra Valley Water — the north and east: Maroondah, Knox, Whitehorse, Manningham, Banyule
• Greater Western Water — the west and north-west

It matters because the allowance process differs between them, and because a fault on the retailer’s side of the meter is their cost, not yours.

The 30-minute meter test

This costs nothing and rules out most guesswork.

1. Turn everything off. Every tap inside and out, dishwasher, washing machine, ice maker, irrigation. Do not flush a toilet during the test.
2. Find your meter, usually near the front boundary in a small covered box.
3. Write down the full reading, including the red digits. The red ones measure small volumes and are the ones that matter here.
4. Some meters have a small spinning dial or star. If it is moving with everything off, water is flowing. That alone confirms a leak.
5. Wait 30 minutes using no water at all.
6. Read it again. Any change means water is going somewhere it should not.

If the reading moved, the next question is which side of the meter. Water escaping before the meter is the retailer’s responsibility. After the meter, on your property, is yours.

Where the leak usually is

In rough order of how often I find them:

• A leaking toilet. The most common and the most underestimated. A cistern that trickles into the bowl runs day and night. Put a few drops of food colouring in the cistern, wait 15 minutes without flushing, and check the bowl. Colour in the bowl means the outlet valve is passing.
• An underground supply line. Common on older properties and larger blocks. Look for an unexplained green or soggy patch that stays wet through a dry spell.
• A hot water unit relief valve. Some discharge is normal; a constant stream is not.
• Dripping taps and worn washers. Individually small, collectively noticeable.
• Irrigation and garden lines, especially where a solenoid has failed part-open.

Applying for a hidden leak allowance

Melbourne retailers generally offer a concession on the excess usage from a concealed leak, meaning one you could not reasonably have seen — underground, under a slab, or inside a wall. A dripping tap you ignored for six months will not qualify.

The usual conditions are:

• The leak was genuinely concealed
• You had it repaired promptly once you knew
• You supply a licensed plumber’s statement or invoice describing the leak and the repair
• You apply within the retailer’s time limit

The amount credited and the exact rules vary by retailer and change from time to time, so check your retailer’s current policy rather than assuming. What I can do is provide the plumber’s statement in the form they ask for, which is the part people usually get stuck on.

Reading the rest of the bill

If usage genuinely has not changed, the increase may not be a leak at all. A Melbourne bill mixes water usage charged per kilolitre with fixed service charges for water and sewerage, plus state government contributions. A quarter with a longer billing period, a seasonal usage tier, or a change to the fixed charges can all move the total without a drop of extra water.

When to call

Call sooner rather than later if the meter moves with everything off, if there is a wet patch that will not dry, or if the bill has jumped by more than about a third with no change in the household. A pressure test on the supply line will locate an underground leak without digging up the whole property, and the sooner it is repaired the stronger the allowance claim.

There is more on early warning signs in how to find a water leak and on keeping usage down in lower your water bill.

Bill jumped and you cannot see why? Call 0407 756 172. I will run the meter test with you and provide the plumber’s report your retailer needs.