Leak Detection in Ontario, CA

Is my Ontario home old enough to worry about hidden leaks?

Age matters, but so does construction. City-stats.com puts the median year built for Ontario homes at about 1980, so a typical house has supply piping that has been in service for decades. Copper of that age can develop pinholes, and older galvanized pipe where it remains can corrode from the inside. Newer neighborhoods such as Ontario Ranch are less likely to have worn pipe, but plastic fittings, appliance hoses and irrigation lines can fail at any age. In both cases, most homes are built on concrete slabs, so leaks under the floor are a common search.

Who handles a leak at the meter or the street?

Ontario Municipal Utilities Company (OMUC), the city-owned utility, supplies drinking water across Ontario. If water is surfacing at the meter box or in the street, contact OMUC Utilities Customer Service at (909) 395-2050 before calling a plumber, since the leak may be on the utility's side. OMUC also reports that its service line inventory confirmed no lead service lines in its system. A leak between the meter and your house is generally on private pipe and becomes a job for a plumber.

Could my sprinklers or a backflow device be leaking?

Yes, and they are worth ruling out early. Irrigation valves, cracked laterals and broken heads account for a lot of unexplained use. Some Ontario properties also have backflow assemblies that OMUC's Water Quality Programs Division requires case by case; those must be tested at least annually by a City-approved tester, and a failing assembly can drip or discharge water. Shutting off the irrigation controller and re-reading the meter is a quick way to split indoor and outdoor plumbing.

A short local note

Ontario's tap water blends City groundwater from the Chino Basin with purchased and imported supplies, and the 2025 Consumer Confidence Report lists City groundwater hardness averaging 124 mg/L. Mineral crust around a valve or under a sink is a common early sign of a slow drip. If a repair needs a permit, the City of Ontario Building Department accepts applications through its Citizen Portal Access website, and the plumber can tell you whether the fix you need falls under that requirement.