Commercial Plumbing Contractor in St. Louis, MO & Surrounding Areas
Legacy Plumbing builds complete commercial plumbing systems for general contractors, developers, and facility owners across the St. Louis metro. We deliver ground-up construction, tenant finish, and industrial work through both design-build and plan-and-spec contracts.
Request a Commercial Quote
Tell us about your project — we respond within one business day.
One Plumbing Contractor from Preconstruction to Final Inspection
Choose the project type or delivery method that fits your job. Our team carries the plumbing scope from early pricing through closeout.
Ground-Up Plumbing Systems
Complete plumbing installations from underground utilities and underslab rough-in through trim, testing, and final inspection.
View Ground-Up Plumbing Systems detailsTenant Finish & Build-Out
Commercial tenant improvements, renovations, and occupied-building build-outs coordinated around the opening schedule.
View Tenant Finish & Build-Out detailsIndustrial & Specialty Systems
Compressed air, industrial waste, equipment connections, and specialty systems for demanding facilities.
View Industrial & Specialty Systems detailsDesign-Build & Design-Assist
Early budgeting, constructability review, coordination, and value engineering before the plumbing design is locked.
View Design-Build & Design-Assist detailsPlan & Spec
Detailed takeoffs, scope-clear hard bids, installation to the engineer's drawings, and complete closeout documentation.
View Plan & Spec detailsUnderground & Site Utilities
Self-performed sanitary, storm, water service, and grease waste with our own excavation equipment.
View Underground & Site Utilities details
Underground & Site Utilities — In-House Across St. Louis
We own and operate our own excavators, skid steers, and mini-excavators so we can self-perform underground sanitary, storm, water service, and grease waste. One trade, one schedule, one point of accountability.
- Underground sanitary & vent
- Storm & roof drain
- Domestic water service
- Grease waste & interceptors
- Site utility tie-ins
- Backflow & meter pits
Commercial Plumbing Across Every Sector
Commercial Service & Maintenance — St. Louis Metro
When a backed-up line or failed water heater threatens revenue, our service division dispatches a stocked truck as scheduled. We support the buildings we build — and the ones we didn't.
- Scheduled service from 7am–4pm Mon–Fri
- Planned preventative maintenance
- Backflow testing & certification
- Water heater & boiler service
- Drain cleaning
- Repipe & leak repair
Our Process
- 01
Preconstruction
Review drawings, site conditions and schedule with your team.
- 02
Design / Estimating
Size systems, value-engineer and deliver a clear, written number.
- 03
Submittals
Fixture, equipment and material submittals approved before ordering.
- 04
Rough-In
Underground and above-ground piping installed, tested and inspected.
- 05
Trim & Startup
Fixtures and equipment set, water heaters started and balanced.
- 06
Closeout
Final inspection, O&M manuals, as-builts and warranty handoff.
Bidding a Project in St. Louis?
Get a bid from a self-performing commercial plumbing contractor headquartered in O'Fallon, MO, serving the greater St. Louis region.