slab leaks

Common Slab Leaks in Commercial Buildings

Many buildings of all kinds rest on concrete slabs due to the durability and availability of the material. While this slap can perform well for years, the moment something starts to go wrong, it can lead to a variety of issues for your business. Slab leaks may start small, but in time, can lead to serious water damage, mold, and mildew in different parts of your business, not to mention ruining product/equipment. As a plumber, you need to know some of the common leaks you may encounter with a concrete slab building and how to address them.

concrete slab leaks construction
Photo by Wood Water Wall

Types of Slab Leaks

So what are some of the slab leaks that are likely to occur in a commercial building? Here’s a rundown of some of the common causes.

Corrosion-based leaks

Pipe corrosion can be a major contributor to a leak under the slab. This tends to happen either when the water gets too acidic or too alkaline. The balanced point you want to aim for is between 6.5 and 8.5 pH. Some people check this with test strips, but a plumber’s reading is likely more accurate.

Abrasion-based leaks

Depending on the layout, some pipes under your slab may readily rub up against concrete, gravel, or even other pipes. When this happens over an extended period of time, the pipes begin to wear down and eventually leak. This is more likely to happen to hot water because the pipes expand with use.

External pressure leaks

Water pressure is the culprit a lot of people blame for leaks, but there are other types of pressure that can happen. For example, depending on where you live, earthquakes, soil erosion, and other issues can cause the dirt to shift under your foundation. When this happens, it puts additional pressure on the pipes, which could cause a slab leak.

Poor construction

This is arguably the most frustrating root cause because it could have been avoided. If the piping was dented during construction or improperly assembled, you are essentially on a timer for a slab leak. With that said, though, slab leaks can also occur when the piping gets past its normal lifespan. If you are planning on buying a commercial property, make sure you get information on when the piping was last changed.

cracks in slab leaks
Photo by timallenphoto

Starting With Concrete Slab Leaks Detection And Repair

So, we’ve established the types of slab leaks you may encounter. How do you use slab leak detection to determine the best course of action? First, there may be a few signs that your customers may report that lead to a slab leak. Here’s a closer look:

Water bill increases

These are always a good indicator that there’s some sort of issue in the plumbing, as long as there isn’t also an increase in water use. Plumbers should always be called, even if the leak ends up not being a slab leak.

Water pools

When a slab leak occurs, water will gather under the foundation until an opening is available. As a part of leak detection, plumbers will generally check along the foundation until they find areas where it appears that water is pouring out. If there’s not something else like a hose nearby, this likely means a slab leak. However, water can pool in other areas inside the property as well, like a bathroom or commercial kitchen.

Flooring issues

These are generally the easiest way for the layman to notice a slab leak. If there isn’t an opening for water to get out of the foundation, it can rise instead until it reaches the floor. This can mean damp or wet carpet or warped hardwood floors.


If you start to smell mold or mildew, which will likely happen before you see it, be sure to look for some of the other signs on this list. Water can cause mold to grow when it gets into the carpet or behind drywall.

Foundation issues

If left untouched for a long period of time, large slab leaks can saturate the soil under the property. When the wet soil is washed away, there’s no support for the foundation, which can lead to cracks. If it gets to this point, both a plumber and foundation repair specialist are likely needed.

slab leaks in concrete
Photo by kenkuza

However, you don’t want to be overly reliant on this method of detection. If your client waits until this point to get service, then they may need to alter or temporarily shut down operations for you to do repairs. In a residential setting, rerouting is often recommended, but for commercial settings, you’re generally best served to do repairs outright. The best way to avoid this happening at an inconvenient time for your clients is to move them towards a service plan. This way, a professional is checking the slab for leak signs of a regular basis and is able to make changes before there’s any noticeable impact.

Final Thoughts on Slab Leaks

Plumbing companies need to be able to adapt quickly when the need for slab leaks repair is discovered. However, not every job is going to have the same time or financial cost on your end. A metal building with a concrete slab may require an entirely different approach from another depending on the soil or type of piping used, for example. The best asset you have to make sure you are putting in the right bids/quotes for slab leaks jobs is project management software like eSUB.

The reason why our product is so useful in these scenarios is that it makes it easy to compare different cost history for various jobs. This empowers plumbers to have a full understanding of exactly the numbers they need to provide to be profitable while also appealing to potential customers. In addition, we can store these records in the cloud so your teams in the field and in the office have access to the same information.

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