Underground Fire Protection
Installation, testing, and repair of underground fire mains and service lines — the foundation that connects your fire protection systems to the water supply.
Everything Above Ground Depends on What's Below
Underground fire protection is 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. If the underground isn't properly installed, tested, and maintained, nothing above ground will perform when you need it.
Hydrotek Fire Systems handles the full scope of underground fire protection — from new installations on development projects and municipal infrastructure, through hydrostatic testing and flushing, to leak repairs and pipe replacements on existing systems. We coordinate with water authorities, utility locators, and civil contractors to deliver work that's built right and accepted on the first inspection.
Our Underground Services
Complete underground fire main solutions for new builds, repairs, and upgrades
New Installation
Complete underground fire main installation for new construction, subdivisions, and site developments — from the water main tap through the building riser connection. Coordinated with civil work, paving, and utility schedules to keep your project on track.
Hydrostatic Testing
All new underground fire mains must be pressure tested before being placed in service. We perform hydrostatic tests at the required pressure and duration per NFPA 24, document results, and provide certified reports for water authority acceptance.
Flushing
Underground mains must be flushed at the required flow rate to clear construction debris, sediment, and foreign material before the system goes live. We verify flow rates, document the flush, and confirm the main is clean and ready for service.
Repair & Replacement
Leaking mains, corroded piping, failed check valves, broken gate valves, and damaged fire department connections — we excavate, repair, and replace underground components to restore system integrity and water supply reliability.
Tie-Ins & Modifications
Adding a new building to an existing fire main, connecting additional hydrants, relocating a fire department connection, or upsizing a service line for increased demand — we handle all underground modifications and extensions.
Valve & PIV Service
Inspection, operation, and repair of underground gate valves, post indicator valves (PIVs), and indicator posts. We verify valve positions, test operation, lubricate, and replace worn components to ensure reliable shutoff and flow control.
System Components
Every component we install is selected for durability and code compliance
Ductile Iron Pipe
The standard for underground fire mains — durable, corrosion-resistant, and rated for high-pressure fire protection service.
Gate Valves
Underground isolation valves that allow sections of the fire main to be shut off for maintenance or repair without disabling the entire system.
Post Indicator Valves
Above-grade valve indicators that show whether underground valves are open or shut — required for fire department and building operator visibility.
Check Valves
Prevent backflow in the fire service line and ensure water flows in the correct direction from the public main to the building.
Fire Dept. Connections
Siamese connections that allow fire departments to pump supplemental water into the building's fire protection system from the street.
Thrust Restraints
Concrete thrust blocks and mechanical joint restraints that prevent underground fittings from separating under water pressure.
Built to Code
All underground fire protection work is performed in accordance with NFPA 24, NFPA 25, and the requirements of the local water authority and AHJ. We coordinate directly with water districts and building departments across San Joaquin, Sacramento, Stanislaus, and surrounding counties to ensure your underground work meets all jurisdictional requirements and passes acceptance testing.
Need Underground Fire Protection?
Whether it's a new fire main for a development project or a repair on an existing underground line — we're ready to help.
Request Service or Estimate