Project Portfolio

South Bay Projects We're Proud Of

18+ years of trenchless sewer replacements, tankless installs, commercial boiler work, and emergency repairs — across every city in the South Bay. Every photo below is a real Mainline job. No stock imagery.

Years: 18+Years
Jobs Completed: 1,000+Jobs Completed
South Bay Cities: 16South Bay Cities
Licensed: C-36Licensed

Case Studies

Precision Plumbing, Documented

Every project below is a property preserved — a yard left intact, a driveway untouched, a weekend not ruined. With 18+years of field experience and hundreds of trenchless sewer replacements completed, owner Jesse Rendon and the Mainline team have built a reputation for solving the infrastructure problems most plumbers won't take on.

Torrance, CAPipe Bursting

Trenchless Sewer Lateral Replacement

An eighty-five-foot sewer lateral beneath a mature, fully landscaped Torrance backyard had failed at multiple points after decades of root intrusion through the original clay pipe joints. Traditional excavation would have meant trenching the length of the yard, removing established trees, and weeks of restoration. We deployed our HDPE pipe-bursting system through two small access pits — one near the house cleanout, one at the city tap — and pulled a brand-new continuous polyethylene line through the path of the old pipe in a single day. Zero landscape disturbance, a fifty-year material warranty, and a homeowner whose backyard looked exactly the same on Saturday morning as it did on Friday night.

Providence St. Joseph Hospital, Orange, CACommercial Plumbing

Overnight Cast Iron Drain Replacement at a Working Hospital

Providence St. Joseph Hospital in Orange needed a failing cast iron drain line replaced in the ceiling of a multi-story public atrium — inside a building that never closes. We scheduled the work overnight to keep patients, staff, and visitors undisturbed, then sealed the entire work zone in floor-to-ceiling poly containment, sheathed the surrounding walls in RAM BOARD, and covered every finished floor surface. An articulating boom lift gave our crew safe access to the atrium ceiling, where we removed the corroded original cast iron and installed new code-compliant cast iron drainage joined with no-hub couplings — the durable, fire-rated material a hospital requires. By the time the hospital opened in the morning, the ceiling access was patched, the containment was gone, and the space was spotless. This is the standard of care we bring to every occupied commercial facility we work in.

Redondo Beach, CATrenchless Sewer Replacement

Pipe Bursting Beneath a Stamped Concrete Driveway

A Redondo Beach homeowner had a corroded cast-iron sewer main running directly under a stamped concrete driveway that had been custom-poured eighteen months earlier. Two competing plumbers quoted full driveway demolition and replacement on top of the sewer work — a five-figure restoration cost on its own. We accessed the line through the existing house cleanout and a single excavation pit at the property edge, then burst the cast iron and pulled new HDPE through the same corridor at the same depth. The driveway was untouched. The homeowner saved more than eight thousand dollars in concrete restoration alone, and the new line carries a half-century manufacturer warranty.

Manhattan Beach, CAWater Heaters

Navien NPE-240A2 Tankless Water Heater Installation

A Manhattan Beach family was on their third failing fifty-gallon tank water heater in twelve years and ready to upgrade for good. We installed a Navien NPE-240A2 condensing tankless unit in the existing garage location, upsized the gas line to support the higher BTU draw, ran dedicated stainless concentric venting through the side wall to code, and added a recirculation loop with a smart timer so the master bath gets hot water in under five seconds. As one of the few Level 5 Navien-certified installers in Southern California, we commission every install to manufacturer spec — meaning the homeowner gets the full Navien warranty and the unit performs at rated efficiency for its entire service life.

Hermosa Beach, CAEmergency Repair & Pipe Bursting

After-Hours Emergency Sewer Backup

A Hermosa Beach homeowner called at nine on a Sunday night with sewage backing into a downstairs shower and the laundry standpipe overflowing. We had a technician on-site within the hour. A high-definition camera inspection traced the failure to a collapsed section of clay pipe at twenty-two feet, with heavy root intrusion at three additional joints further out. We cleared the immediate blockage that night to stop the active backup, then returned the next morning to pipe-burst the entire forty-foot run from house to city tap with HDPE. Total elapsed time from emergency call to permanent fix: under eighteen hours.

Gardena, CARepipes

Whole-Home PEX-A Repipe

A 1960s Gardena ranch home had original galvanized hot and cold supply lines that were rust-restricted to a fraction of their original interior diameter — water pressure at the master shower had dropped to a trickle. We executed a complete whole-home repipe in PEX-A using the home-run manifold method: every fixture gets its own dedicated line back to a central manifold in the mechanical closet, eliminating pressure loss when multiple fixtures run simultaneously. We patched every drywall opening cleanly, pressure-tested the system to one hundred PSI for the city inspection, and restored full factory-spec water pressure throughout the house. The new system carries a twenty-five-year manufacturer warranty against material failure.

Carson, CACommercial Plumbing

Raypak 399B Commercial Boiler Replacement

A forty-eight-unit Carson apartment complex was running on an aging atmospheric Raypak boiler that had become unreliable through three winters of cold-water complaints. As certified Raypak commercial installers, we scoped the replacement, decommissioned the old unit safely, and installed a new high-efficiency Raypak 399B condensing boiler with full BMS integration so the on-site property manager can monitor performance, modulation, and fault codes from a single dashboard. We coordinated the change-over to a six-hour window overnight to minimize tenant impact, ran new venting to current South Coast AQMD spec, and commissioned the unit to manufacturer combustion-tuning standards before sign-off.

Palos Verdes, CACured-In-Place Pipe Lining

CIPP Sewer Line Rehabilitation on a Hillside Property

A Palos Verdes hillside home had a sixty-five-foot sewer line dropping at a steep grade through a terraced garden, with a single accessible cleanout at the top of the slope and no practical excavation route on the hillside itself. We solved it with cured-in-place pipe (CIPP) lining: a saturated felt liner, pulled through the existing pipe with compressed air, then cured in place with steam to form a seamless structural pipe-within-a-pipe. No trenching on the grade, no terraced garden disturbed, and a fully restored sewer line with a fifty-year design life — installed entirely through one cleanout access point.

Rolling Hills Estates, CAGas Lines

Custom Outdoor Gas Line & Fire Pit Hookup

A Rolling Hills Estates homeowner was building a custom backyard kitchen and entertainment area centered on a hand-built stone fire pit and wanted a permanent natural-gas line run rather than the typical propane-tank workaround. We pulled permits with the city, ran a properly sized black-iron line from the meter through a sleeved underground corridor to the fire pit location, integrated a code-compliant emergency shutoff in a hardscape-flush valve box, and pressure-tested the entire system at one and a half times working pressure for inspection. Final result: a clean, permitted, code-compliant gas hookup that integrates seamlessly with the finished hardscape.

El Segundo, CAHydro Jetting

High-Pressure Hydro-Jetting for a Restaurant Grease Line

An El Segundo restaurant was losing service hours weekly to a chronically blocked one-hundred-and-fifty-foot grease-line that snake augers could only partially clear. We brought in our four-thousand-PSI commercial hydro-jetter, deployed a rotating-nozzle head, and hydro-scoured the entire line down to bare pipe walls — removing decades of solidified grease, food solids, and mineral scale that augers leave behind. A post-job camera inspection confirmed full pipe-wall recovery from end to end. We then set the kitchen up on a quarterly preventative-maintenance jetting schedule so the line stays at flow capacity year-round.

Hawthorne, CAWater Main Repair

Main Water Line Replacement

A Hawthorne homeowner had a corroded galvanized water service running from the meter to the house that had developed multiple pinhole leaks over the prior six months, with water bills creeping up and a soggy strip in the front lawn the giveaway. We pulled the city permit, exposed the meter and house entry points with two small access pits, and replaced the entire service with one continuous run of type-K copper at proper burial depth. No trenching of the front lawn between the access points, full pressure restoration to the house, and the new line carries a fifty-year service life. We pressure-tested to one and a half times working pressure for the city sign-off before backfilling.

Lomita, CASlab Leak Repair

Slab Leak Reroute Through the Foundation

A Lomita ranch home had its second slab leak in eighteen months — both on the original 1970s copper hot-water supply running under the foundation slab. Rather than chase another spot repair through the concrete, we recommended a full reroute: abandon the under-slab supply lines, run new PEX-A overhead through the attic, and drop down inside walls to each fixture. We installed a new manifold in the mechanical closet, ran every fixture as a dedicated home-run line, abandoned the failed slab piping in place under pressure cap, and pressure-tested the new system. Total job time: two days, including drywall patching. The homeowner gets a system that will never have another slab leak — because there is no longer any pressurized water under the slab.

San Pedro, CAWater Filtration

Whole-Home Carbon Filtration Install

A San Pedro family wanted to address hard-water scale on fixtures and the chlorine taste from the municipal supply without resorting to bottled water or constant under-sink filter cartridges. We tested their actual water at the tap (hardness, chlorine, TDS, pH), specified a three-stage whole-home system — sediment pre-filter, high-capacity carbon, and a softener stage — and installed it at the main supply line just past the meter and pressure regulator. Every tap in the house now delivers softened, chlorine-free water. We set up a maintenance schedule with the homeowner: pre-filters every six months, carbon media every twelve, softener resin checked annually. The whole install was a half-day job with permit sign-off.

Long Beach, CASump Pump

Sump Pump Replacement Before the Storm Season

A Long Beach homeowner with a basement-level mechanical room had a primary sump pump that was running constantly but barely keeping up — the impeller had worn and discharge volume had dropped to a fraction of rated capacity. We replaced the primary with a higher-flow cast-iron submersible pump, added a battery-backup secondary pump as insurance for power outages during winter storms, integrated a high-water alarm on the basin lid, and routed new schedule-40 PVC discharge piping to daylight away from the foundation. The homeowner now has redundancy, real-time alarm coverage, and a system rated for the heaviest storm seasons the South Bay throws at it.

Inglewood, CAGeneral Plumbing

Pressure Reducing Valve Replacement

An Inglewood homeowner was hearing water-hammer thumping in the walls every time a fixture closed and had multiple toilet fill valves wear out faster than they should — both classic symptoms of high incoming water pressure. A pressure test at the hose bib showed inlet pressure at one hundred and twelve PSI (the safe range is forty-five to eighty). We replaced the failed pressure reducing valve at the main supply line, dialed it down to a regulated seventy PSI, and installed a thermal expansion tank on the water heater outlet to absorb pressure spikes from heating cycles. Water-hammer gone, fixtures protected, and the homeowner's water heater warranty preserved (high pressure voids it).

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