Sub-Slab Leak Repair Stockton and Modesto

Residential slab leak detection & repairs in the Central Valley

With one of California’s highest concentrations of slab-foundation homes, the Central Valley sees frequent slab leaks, especially in areas like Stockton and Modesto. Accurate detection is essential, which is why many homeowners begin with our professional leak detection services in Modesto and Stockton.

Our repair process starts by setting up containment as meticulously as a surgical prep, using zip walls to keep dust and debris from spreading. To avoid damaging post-tension slab cables, we scan and mark cable locations before jackhammering and excavating to expose the buried copper piping. After removing the leaking section—often no bigger than a pinhole—we test the system, make the repair, and conduct a final pressure test. Once confirmed, the area is back-filled and the concrete patched to match the existing slab.

As a leading sub-slab leak repair company in Stockton and Modesto, we back our work with a one-year warranty.

Types of sub-slab piping

Soft-rolled copper pipe | steel water pipe | copper hard pipe

The sub-slab copper piping that is most common is a soft-rolled copper pipe, installed in the ground before the concrete is poured. It was used for many years because it allowed plumbers to lay long sections of pipe across the house without slowing down the construction process.

Soft-rolled copper also enabled the installation of pipe lengths without connecting fittings under the slab. Each end of the copper pipe would rise into the wall and connect to the supplied fixture, as well as to additional piping feeding other fixtures. This connection point is typically referred to as a manifold (see photo B).

Homes built before the mid-1970s often used an outdated building practice where pipes were installed under the slab with below-grade fittings feeding each fixture or additional location. This often resulted in broken sub-slab fittings (see photo A). Some of these homes were plumbed under the slab with steel water piping, while others used copper hard pipe. Our technician can usually identify the piping layout during the initial inspection. The only repair options for sub-slab hard pipe are to excavate the leaking location and replace a small section of the pipe or abandon the underground piping and repipe overhead.

Sub-Slab Construction

Concrete-slab homes are still made these days but current building codes require a chase pipe or conduit surround the piping and transition fittings must be located above grade.

Most residential concrete slabs are between 3 and 10 inches thick. The perimeter of the home and the load-bearing areas are typically 2-3 feet thick. The concrete is poured all at once to create a continuous connection between the concrete floor and the foundation.

Before pouring the concrete, contractors and plumbers install the sewer and water pipes at a depth of approximately 12 inches to 4 feet. This piping is positioned to align with the planned locations of the plumbing fixtures.

Usually, the contractor places a Visqueen waterproof barrier and then a layer of gravel before pouring the concrete. As a result, homeowners often do not see moisture or water surfacing in the home from an underground slab leak, as the water drains into the ground and away from the home.

Call or request sub-slab leak repair Stockton services online!