A shower leaks through the floor when water escapes from the pressurised plumbing feeding it or the use-only side carrying it away. Supply pipes and the mixer behind the wall hold water even when nobody is showering. The floor waste junction, grout, silicone and membrane sit on the use-only side, and a reseal or regrout fixes only grout and silicone.
At Exceed Plumbing, we read a change in SA Water’s meter test, after an hour or two without water, as a likely pressurised-side leak. In South Australia, pipework needs a licensed plumber and a compliance certificate within 7 days, while waterproofing is registered building work. This guide covers causes, signs, the meter test and when a concealed leak may be eligible for SA Water’s leakage allowance.
Why a Shower Leaks Through the Floor
A stained ceiling under the shower points to water escaping from the shower’s plumbing or its waterproofing. The national building code says every wet area must prevent that from happening:
That rule sits in the Australian Building Codes Board’s National Construction Code. In bathrooms, laundries and similar rooms, “water must be prevented from penetrating” behind fittings and linings or into concealed spaces. Building to Part 10.2 of the ABCB Housing Provisions satisfies that requirement.
South Australia adds its own variations. Bathroom floors must be “installed in a manner that will prevent accumulation of water on the surface which could create unhealthy or hazardous conditions.” A wet area floor containing a vessel must also be “graded to a floor waste to permit drainage of water.”
A stain downstairs suggests one of those barriers has failed, on one of two sides. The pressurised side is the supply pipework and the mixer body behind the wall, holding water around the clock.
On the use-only side sit the grout, silicone, waterproofing membrane and floor waste connection, which only get wet while the shower runs. Regrouting deals with one small part of this side and nothing at all on the pressurised side.
Common Causes of a Leaking Shower Floor
Why does a shower keep leaking after a fresh reseal? Only one of the six causes below is failed grout or silicone, and a reseal leaves the other five untouched:
- Supply pipe leak behind the wall. The hot and cold lines stay pressurised, so a weeping joint keeps feeding water into the floor. Repairing a burst or leaking pipe is licensed work.
- Mixer body behind the tiles. The mixer, where hot and cold lines meet, is pressurised too. A worn mixer is a leaking tap repair, not a waterproofing job.
- Floor waste and membrane junction. Under Part 10.2 Wet area waterproofing, the membrane must be “terminated at or in the drainage flange to provide a waterproof connection”. If that junction fails, water runs under the tiles, not down the drain.
- Failed grout or silicone. Cracked grout and perished silicone let water reach the tile bed. It’s the only cause a reseal fixes.
- Failed membrane. Part 10.2 requires the shower floor, wall and floor junctions and penetrations to be waterproof. Replacing a failed membrane is waterproofing work, not plumbing.
- Poor falls and ponding. Where a floor waste is installed, Part 10.2 sets the fall to the waste between 1:80 and 1:50, so ponding is a code-level concern.
More: How To Fix a Leaking Shower Tap
Warning Signs Below and Around a Leaking Shower
A quick look at the ceiling below, the skirting and the shower floor tells you plenty. Damp, staining, loose tiles and a musty smell are classic signs of a leak:
According to SA Water, “Damp, warped, or discoloured walls, floors, or carpets can suggest a concealed leak indoors.” SA Water also warns that some leaks go unnoticed until the next water bill arrives.
In Queensland, the building regulator’s QBCC waterproofing snapshot lists these warning signs, and they read well for any tiled shower:
- Peeling, bubbling or blistering paint
- Peeling or discolouring silicone joints
- Discoloured or stained ceilings and walls
- Damp patches that worsen after showers or rain
- Loose tiles or crumbling grout
- A persistent musty smell or mould growth
The Queensland regulator also notes that “Waterproofing failures often develop slowly.” That’s why a small stain deserves attention now rather than after the next bill.
Watch the floor waste too. Water that ponds or drains slowly around the grate can point to a blocked shower drain, so clear that before blaming the membrane.
More: Clogged Shower Drain? Causes and How to Clear It Safely
The SA Water Meter Test for a Hidden Shower Leak
Can your water meter show which side is leaking before anyone lifts a tile? SA Water publishes a four-step meter test, and here is how our plumbers read the result:
The steps, quoted word for word:
- “Take an initial reading from your water meter.”
- “Avoid using any water inside and outside of your house for about an hour or two.”
- “Take another reading.”
- “If the reading has changed, there’s likely a leak.”
SA Water’s Easy English guide says to wait 2 hours and places the meter “in the ground in your front garden”. Lift the lid to read it, but SA Water asks you not to fix or interfere with the meter.
Our plumbers at Exceed Plumbing apply their own reasoning here, not an SA Water rule. The meter only counts water drawn through the supply, so a change with every tap off points to the pressurised side. A steady meter suggests a sound supply side, pointing instead to the floor waste, grout, silicone or membrane.
The meter catches every leak on the property, from garden taps to the hot water unit and toilet. For the cistern, SA Water suggests a few drops of food colouring: colour in the bowl without flushing means a leak. A leaking cistern needs a toilet repair, not a shower fix.
Plumber or Waterproofer for a Shower Leak in South Australia
Paying for the wrong trade wastes time and money. In South Australia, pipework and drainage need a licensed plumber, while waterproofing is building work regulated by Consumer and Business Services:
According to SA.GOV.AU, a business doing plumbing work must hold a plumbing, gas fitting and electrical (PGE) contractor’s licence. Anyone doing the physical trade work must also be registered as a plumber.
Consumer and Business Services (CBS) lists “waterproofing of wet areas and balconies” as a separate category in its registration conditions for building work supervisors. Membrane work belongs with a trade registered for it.
Some shower work is legal to do yourself. SA.GOV.AU’s DIY plumbing list lets homeowners with the skills “replace or repair a tap” and “change a shower head”. By law, though, “altering any pipework” needs a licensed plumber.
Licensed work comes with paperwork. SA.GOV.AU says you should receive a plumbing eCoC (electronic certificate of compliance) within 7 days for sanitary plumbing, drainage and pipework from the mains supply.
It also warns, “Without an eCoC for these works, insurance companies could refuse claims if the related works cause a fire or damage.” Our plumbing services are carried out by our own licensed team.
More: What To Do If You Have a Pipe Leaking in the Wall
SA Water Leakage Allowance and Mould After a Leak
A concealed leak may be eligible for SA Water’s leakage allowance, covering “fifty per cent of lost water”. The utility says it can be claimed only once every five years:
SA Water’s leakage allowance application says the leak must be “concealed or not easy to see” and fixed by a licensed plumber with authorised materials. Repair it within four weeks of noticing it or receiving a high water use notice. Apply within six weeks of the repair date or the next bill.
Keep the plumber’s invoice and take a meter reading after the repair, as SA Water asks for both. SA Water excludes “Fixtures (internal and external taps)”, hot water systems and toilet cisterns.
With the leak fixed, tackle any mould. SA Health says the most common moulds are not hazardous, though some can trigger asthma or hay fever.
Small areas can be cleaned with a bleach mixture of “1 part bleach to 3 parts water” or a suitable commercial product. Don’t dry-brush, and call a professional cleaner for extensive mould. SA Health warns, “If mould returns, there may be an underlying problem.”
Conclusion on Finding a Shower Leak
A shower that leaks through the floor needs a diagnosis before a repair, because a reseal reaches only part of one side. Keep these three points in mind before booking:
- Two sides, two kinds of fix. Supply pipes and the mixer hold water around the clock, while grout, silicone, membrane and floor waste leak only in use.
- Test before you pay anyone. Read the meter, use no water for an hour or two, then read it again. We treat a change as a likely pressurised-side leak once the cistern is ruled out.
- Know the South Australian rules. Pipework needs a licensed plumber and an eCoC within 7 days, and membrane work is CBS-registered. A concealed leak may be eligible for an SA Water allowance on half the water lost.
Adelaide Suburbs We Service
Our team at Exceed Plumbing finds and fixes the plumbing side of shower leaks across metropolitan Adelaide and the Hills. That includes supply pipes, mixer bodies and floor waste connections:
We attend leaking showers, damp floors and stained ceilings in Colonel Light Gardens, Happy Valley and West Beach. The same licensed team handles Elizabeth plumbing, Paralowie plumbing, Noarlunga plumbing, Stirling plumbing and Goodwood plumbing, plus the suburbs around them.
Book a Shower Leak Plumber in Adelaide
If the ceiling stain keeps spreading or the meter test showed a change, call Exceed Plumbing on 0456 461 354. Our licensed plumbers find the source before recommending any repair:
- Aiming to reach you within the hour, 24/7
- Free quotes and fixed upfront pricing before work starts
- Licensed plumbers, Licence 333997, no subcontractors
- Lifetime Labour Warranty on workmanship
Membrane faults are different. If the source turns out to be the membrane rather than the plumbing, that work belongs with a CBS-registered waterproofer.
Frequently Asked Questions About Leaking Shower Floors
How can I tell if it’s a pipe leak or a waterproofing leak?
Run SA Water’s meter test over an hour or two of no water use. We read a change as a likely supply leak, while a steady meter points to grout, silicone, membrane or floor waste.
Will resealing the grout fix a leaking shower?
Only when cracked grout or perished silicone is the cause. A reseal can’t fix a leaking supply pipe, mixer, membrane or floor waste connection, so find the source first.
Do I need a plumber or a waterproofer in South Australia?
Either one, depending on where the leak starts. Supply pipework and drainage need a licensed plumber, who issues an eCoC within 7 days. Waterproofing is building work regulated by Consumer and Business Services.
Will home insurance cover a leaking shower?
It depends on the policy, so check its product disclosure statement. ASIC’s home insurance review says damage from “wear and tear” or a failure to maintain property in “good condition” is generally excluded.
Can I get money back from SA Water for a hidden leak?
You may be eligible if a licensed plumber repaired a concealed leak. SA Water’s allowance covers fifty per cent of lost water, once every five years, excluding taps, hot water systems and cisterns.
Does Exceed Plumbing find and fix shower leaks in Adelaide?
Yes, on the plumbing side. At Exceed Plumbing, our licensed plumbers find the source and repair supply pipes, mixers and floor waste connections across Adelaide. Membrane work belongs with a CBS-registered waterproofer.
