A hidden leak is the one you never see. It runs underground or inside a wall, it does not show up as a puddle, and the first anybody knows about it is a water bill several times the usual size.
If a licensed plumber has found and repaired one, Sydney Water may credit part of the usage back. It is not automatic and it is not guaranteed, but it is worth asking for, and the details they want are exactly the ones that should already be on your invoice.
Once a licensed plumber or qualified technician has repaired a hidden leak, call Sydney Water on 13 20 92 and ask for a hidden leak allowance. If it is approved it is a goodwill credit for 50% of the water usage charge on the most impacted quarter. You must report it within a year of the repair, and there must have been no hidden leak allowance on that property in the past five years.
- Get the leak found and repaired by a licensed plumber
- Keep the invoice: business name, ABN, phone and licence number
- Call Sydney Water on 13 20 92, 8am to 5:30pm weekdays
- Apply within a year of the repair
- Only the owner or an authorised contact can apply
On this page
1. What counts as a hidden leak, and what does not
The distinction is the whole thing, and it is stricter than people expect. The allowance is for leaks you could not reasonably have seen. If it was visible, it is not covered.
Sydney Water is explicit that visible leaks are excluded, and that includes damp soil and consistently wet grass. Those are visible signs, even though nobody thinks of a wet patch on the lawn as a leak.
Also excluded: taps, toilet cisterns, dishwashers and washing machines. A running cistern can waste a genuinely startling amount of water, but it is a visible fixture fault rather than a hidden leak. Vacant land and unoccupied properties, including building sites, do not qualify either.
It is the exclusion that catches people out most often. If there has been damp ground or green grass in a dry spell, that counts as visible, however long it went unrecognised.
2. What the allowance actually is
It is a goodwill credit for 50% of the water usage charge on the quarter that was most affected. Both residential and non-residential property owners can receive it.
Two things follow from that wording. It is half, not all, so a large leak still costs money even when the allowance is granted. And it applies to the usage charge on one quarter, so a leak that ran across several billing periods is not credited across all of them.
It is also described as goodwill, which means Sydney Water decides. We can tell you the conditions and give you the paperwork. We cannot promise you an outcome, and any plumber who does is guessing.
3. The conditions, in plain terms
- Repaired by a licensed plumber or qualified technician. This is the one that connects the allowance to the licence.
- Reported within a year of the repair. Not a year from the bill, a year from when it was fixed.
- No hidden leak allowance on the property in the past five years. It is a property-level rule, so a previous owner's claim still counts.
- Applied for by the owner or an authorised contact. A tenant cannot lodge it themselves.
- The leak was genuinely hidden. See the exclusions above.
We have set out the conditions as Sydney Water publishes them. For anything specific to your property or your account, they are the authority, not us.
4. What to have in front of you when you call
Sydney Water asks for the licensed plumber's or qualified technician's business name, ABN, contact phone number and licence number where applicable, along with their invoice.
That list is the reason we put the licence number and the ABN on every invoice we issue rather than only on the ones where somebody asks. It costs us nothing and it is the difference between making this call in five minutes and chasing a tradesperson for details three months later.
Call 13 20 92, between 8am and 5:30pm Monday to Friday, excluding public holidays.
Suspect a hidden leak?
We will find it, repair it, and give you an invoice with everything Sydney Water asks for.
5. How to catch a hidden leak before the bill does
The meter is the tool, and the test takes about half an hour of doing nothing.
- Turn off every tap and appliance that uses water, and do not flush anything.
- Read the meter, including the small dials, and write it down.
- Leave it for 30 minutes with no water used at all.
- Read it again. Any movement means water is going somewhere.
Do the test when nobody will absent-mindedly use a tap, which usually means before bed or before anyone gets up. If the meter has moved and you cannot see why, that is the point to call somebody.
The other early signals are a bill that has jumped without any change in the household, the sound of running water when nothing is on, and unexplained damp inside. That last one is worth acting on quickly for reasons beyond the bill.
6. If you rent the property
The allowance is applied for by the owner or an authorised contact, so a tenant cannot lodge it directly. That does not make it irrelevant to renters, because a tenant may well be the one paying the water usage.
The practical move is to tell the owner or agent promptly, in writing, and pass on the plumber's invoice details. Whether they apply is their decision, but they cannot apply for something nobody told them about, and the one-year window runs from the repair.
- Sydney Water may credit 50% of the water usage charge on the most affected quarter.
- The leak must have been genuinely hidden. Damp soil and wet grass count as visible.
- Taps, cisterns, dishwashers and washing machines are excluded.
- Report within a year of the repair, and only if there was no allowance in the past 5 years.
- You need the plumber's business name, ABN, phone and licence number, plus the invoice.
Hidden leak allowance FAQs
How much is the Sydney Water hidden leak allowance?
It is a goodwill credit for 50% of the water usage charge on the quarter that was most affected, available to both residential and non-residential property owners. It is half rather than all, and it applies to one quarter.
How do I apply?
Call Sydney Water on 13 20 92 between 8am and 5:30pm Monday to Friday, excluding public holidays, once a licensed plumber or qualified technician has repaired the leak. Have their business name, ABN, contact phone number and licence number ready, along with the invoice.
Is there a time limit?
You need to tell Sydney Water within a year of the repair being carried out. There is also a property-level limit: no hidden leak allowance can have been provided on that property in the past five years.
My grass was green over the leak. Does that still count as hidden?
Sydney Water lists visible leaks as excluded, and specifically includes damp soil and consistently wet grass in that. So a leak that showed itself on the surface is unlikely to qualify, even if nobody realised what it was at the time.
What about a running toilet, that wastes a lot of water?
It does, but toilet cisterns are expressly excluded, along with taps, dishwashers and washing machines. Those are visible fixture faults rather than hidden leaks. Worth fixing quickly for the bill regardless.
Can you guarantee I will get the allowance?
No, and we would be careful of anyone who does. It is described as a goodwill credit and Sydney Water decides. What we can do is find and repair the leak properly and give you an invoice with every detail they ask for on it.