Underground Fire Protection

Installation, testing, and repair of underground fire mains, service lines, and piping that connect your building’s fire protection systems to the public water supply.

What Is Underground Fire Protection?

Underground fire protection refers to the below-grade piping network that delivers water from the public water main to your building’s fire sprinkler system, fire hydrants, fire pumps, and fire department connections. It’s the foundation of your entire fire protection water supply — if the underground piping isn’t properly installed and maintained, nothing above ground will work when you need it.

What We Install

We install complete underground fire service lines including ductile iron and PVC fire mains, gate valves, post indicator valves (PIVs), check valves, fire department connections (FDCs), thrust restraints, and all associated fittings and connections. Every installation is coordinated with the local water authority, utility locators, and civil contractors to ensure proper depth, backfill, and separation from other utilities.

New Construction & Site Development

For new commercial developments, subdivisions, and industrial sites, we handle the underground fire protection scope from the water main tap through the building riser connection. We work from civil engineering plans, coordinate with the general contractor’s site work schedule, and make sure the underground is in place and tested before concrete slabs and paving go down. Our installations are built to pass water authority acceptance testing and AHJ inspection the first time.

Testing & Inspection

All underground fire mains must be hydrostatically pressure tested and flushed before being placed in service — per NFPA 24 and local water authority standards. We perform hydrostatic tests at the required pressure for the required duration, conduct flushing to clear debris and verify flow, and provide certified test reports. For existing systems, we perform periodic inspections of exposed piping, valves, and connections per NFPA 25.

Repair & Replacement

Leaking mains, corroded piping, broken valves, failed check valves, and damaged fire department connections — we excavate, repair, and replace underground fire protection components to restore system integrity. Underground leaks and failures can compromise water supply to your entire fire protection system, so we treat these as high-priority service calls and work to get your system back online as quickly as possible.

Compliance

All underground fire protection work is performed in accordance with NFPA 24 (Standard for the Installation of Private Fire Service Mains and Their Appurtenances), NFPA 25 for ongoing inspection and maintenance, and the requirements of the local water authority and AHJ. We coordinate directly with water districts and building departments across San Joaquin, Sacramento, and Stanislaus counties to ensure your underground work meets all jurisdictional requirements.