How To Find and Repair Concrete Slabs That Leak



A slab leak is an industry term for a leak within the waterline piping below the concrete floor. Slab leaks are an issue in homes and buildings of all ages. A water leak under the floor can easily develop into a costly and inconvenient endeavour. The faster a leak is detected and repaired, the lower the underground water pipe leak repair cost is likely to be.

Continuing from our previous post on how to find & detect water leak in walls, in this post we will talk about how to detect a water leak under a concrete slab, covering how to identify if your slabs have water leak, how to find a water leak, and how to repair it.



Slab Leak Signs

slab leak symptoms


Faucet turned off but sound of water persists

This is a common indication of a leak in under slab water tanks or water pipes in a concrete floor. Modern equipment can detect and repair the leak with non-destructive methods utilising modern technology. This includes approved electronic amplification equipment supported by electromagnetic pipeline locators.

Related: Equipment for water leak detection in Melbourne


Floor hot spot could show hot water line leak

A “spot repair” involves creating an access point into the slab at the point of the determined leak. This is done in order to make a repair to the leaking pipe. It is recognised as a cost-effective slab leak repair option for more recent constructions.

For older systems, rerouting or replacing sewer pipe under the basement floor, including the entire line that was leaking, is considered the most effective method. For leak location purposes, highly trained technicians may employ non-invasive detection equipment to accurately determine the location of the leak. This saves you time and avoids needless property damage.


Mildew or excessive moisture under carpets

damp carpet

A damp carpet or rug with the presence of mould or mildew, accompanied with a peculiar odour could be one of the first indications of a cracked slab. This will require the floor covering to be lifted and an inspection must be carried out in the event of a concentring moisture presence.


Cracks in the walls or flooring

cracks slab

The appearance of cracks in your walls or flooring can be due to the saturation of the foundation, causing moisture to start leaking into the house. This can result in the foundation cracking or buckling. If this is the case, you may also observe cracks in the foundation on the outside of the building.


Wet baseboards

Should you encounter wet baseboards then it could be the result of pressure on the foundations. Any crawl space or basement home built on clay soil can experience soil movement that adversely affects the foundation. When saturated with excessive water clay soils expand and then contract when dry. The continual swelling and shrinking creates pressure on the foundation. And if the foundation cracks, moisture can enter the home. As the floor joist weakens, the flooring above can sag. Moisture attracts various insects such as silverfish, millipedes, and centipedes.


Water coming out below the water heater

Any leak in your water heater is not intermittent and should not be ignored. Due to the tank always being full, a leak will distribute water all around the outer lining of the tank. Generally, it is an issue related to water condensing, with a leak becoming obvious when access panels are removed.


Water on the floor or wet carpet

A wet carpet is a strong indication of a leak. If it concerns water on a tiled floor, then it could be sufficiently severe to cause water to gather in the space between the adhesive and the tiles. Replacing a shower drain in a concrete floor is a common outcome along with repairing and replacing tiles.

There may also be other indications in the case of hardwood floorings, such as a raised (dome-shaped) or warped section. This is a sign that could warn you of serious damage regarding the foundations.


High water bills

A well above average water bill is a general sign of a leak in your home. Although it could be an indication of a water leak from the pool, it could also be warning you of a leak under the slab. Therefore, if after preliminary checks of the concrete slab drain and other areas have been completed without discovering the source, seek professional help.


Wet planters near the house

Any type of wet source against a house is a serious issue, as it can be the cause of damage to foundations and encourage termites. You should ensure that the ground is graded away from the walls. And if you have any doubts, consult a professional leak detection specialist in Melbourne. If there is a grading-related drainage issue, or you’re having trouble locating water lines and pipes underground, seek qualified help to have it corrected.


Finding Your Slab Leak

finding your slab leak

Check your water meter

Severe leaks or multiple minor water leaks can sometimes be detected by performing a simple leak check. After turning off all water supply sources, record the reading of the water meter, wait at least 15 minutes while keeping the water supply off, then check the meter again. Should there be a recorded water usage during this period, then a leak is likely.


Locate your house’s pipes

Knowing the location of the main water supply is as important as an awareness of where to turn off or reset an electric breaker. Your home should have a main water shut-off valve installed inside, in the case of emergency situations and repairs. However, it is also worth taking a tour through your home and making note of how the plumbing system is structured.


Perform an initial pressure test of your home

Testing the water pressure in your home can be easily completed, with an inexpensive pressure gauge. In fact, adjusting the water pressure is one of the top ways to reduce stress on your plumbing system to prevent water pipe leaks in the first place. Testing the water pressure periodically can help pre-empt a problem before a high pressure can damage the plumbing.


Perform complete electronic leak detection service

Special, non-invasive equipment is available for the purpose of definitive diagnoses regarding water leaks in your home. Electromagnetic pipeline locators, electronic amplification equipment, and camera inspections like drainage CCTV, are all examples of devices employed in the detection and location of a leak or leaks beneath your foundations.


Slab Leak Repair

slab leak repair

Spot repair

This type of leak repair involves an excavation of up to 1m² to repair the section of leaking pipe. Although this may be a cheaper option, a pipe that is in a poor condition should be replaced or the drain cleared and relined, since a repair may only provide a short-term solution.


Re-pipe or Reroute

The occasion can arise whereby it is necessary and even more cost-effective to re-pipe or reroute due to a slab leak that is not accessible to repair. This could include a water leak under a bathtub, shower unit or beneath a kitchen cabinet. Knowing your home’s plumbing system and the common sources of household water leaks is helpful, but sometimes it takes more than a repair to stop a leak.


Epoxy pipe coating

The epoxy coating process is simple. However, it offers highly effective pipe restoration technology that coats the inside of pipes completely. The end result means that you will never have to be concerned about pinhole leaks, weak water pressure, and pipe corrosion or contaminants filtering into your water supplies.


Direct Access

The responsibility related to the pipework that conducts clean water is shared between water companies and property owners. Water companies are expected to maintain up-to-date plans of the sewers and watermains for which they are responsible. However, the majority of pipes within individual property boundaries are the responsibility of the property owners. Therefore, property owners have the obligation to maintain those pipes and ensure adequate and safe access to them. Keeping this in mind when making any home renovations or repairs can help you avoid needing to reroute or repipe plumbing due to inaccessibility.


Plumbing services

There are plumbing services offering leak detection in Melbourne that employ highly trained and qualified technicians to conduct household plumbing and concrete slab leak detection and repair. They will use non-invasive leak detection equipment to accurately locate leaks, providing a valuable service that avoids unnecessary property damage.