Slab Leak Repair in Ontario, CA

Is my Ontario house likely to have a slab leak?

Most Ontario houses sit on slab-on-grade foundations, with water lines run through or under the concrete. Census survey figures via city-stats.com put the city's median build year at 1980. Copper that has been buried for forty-plus years can thin where it rubs against rock or rebar, and original joints can loosen with time. Newer homes in Ontario Ranch are less likely to have worn pipe, but a fitting damaged during construction can still fail. A meter that keeps moving with everything off is the first thing to check.

Does Ontario's water play a part?

OMUC water is mostly Chino Basin groundwater from city wells, plus purchased groundwater and imported State Water Project water. Its 2025 report lists city groundwater hardness averaging 124 mg/L and imported water averaging 91 mg/L. That is moderately hard water that leaves scale in heaters and fixtures; the report does not link it to leaks under slabs. OMUC also reports that its lead service line inventory found no lead service lines in its system. For a question about your water, OMUC Utilities Customer Service is (909) 395-2050.

What does a repair involve here?

Once the leak is pinpointed, there are usually two paths. A spot repair opens a small section of floor, replaces the failed piece and patches the slab. A reroute abandons the buried line and runs new pipe through the attic or walls, which keeps the floor intact and often makes sense when the pipe is old or has leaked before. Larger reroutes and repipes go through the City of Ontario Building Department, which takes applications electronically through its Citizen Portal. A plumber can tell you what your job requires.

A local note

Ontario summers are long and hot, which hides hot-side warmth, and high summer bills are easy to blame on irrigation. Run a meter test with the controller off before drawing conclusions. If the meter moves, call soon: water under concrete can wash out the base material and damage the flooring above. Tell the plumber whether the house has had earlier leaks or partial repipes, since that history often decides between a spot repair and a reroute.