# New Construction Plumbing in O'Fallon, MO > Commercial and new construction plumbing in O'Fallon, MO: underground, rough-in, set and trim, bid-spec or design-build. Local crews. Request a bid today. Canonical: https://legacyplumbingmo.com/commercial/new-construction-plumbing-ofallon-mo Commercial Legacy Plumbing is based in O'Fallon, and new construction is a core part of our work: underground sanitary and storm tie-ins, overhead and in-wall rough-in, restroom groups, water heaters, backflow and final trim. We price and build commercial, industrial, multifamily and tenant projects for GCs and owners, working from bid-spec drawings or as a design-build partner. We also serve residential customers for service work, but this page is for the people planning a building: GCs, developers and owners in O'Fallon. Request a Bid ## Request a Bid Send drawings and your bid date. ## Scope of Work on an O'Fallon New Build On new construction, plumbing is a series of inspections and handoffs, so we plan by the sequence of the job: - **Underground:** sanitary and storm laterals to the building, floor drains, interceptors where required, and domestic water service piping coordinated with the site contractor ( [underground and site utilities](https://legacyplumbingmo.com/commercial/underground-site-utilities) ) - **Slab and below-grade rough-in:** under-slab piping, trench drains, sleeves and stubs set to the architectural and structural drawings - **Overhead and in-wall rough-in:** waste, vent, storm and supply piping, restroom carriers, and coordination with mechanical, electrical and fire protection above the ceiling - **Set and trim:** fixtures, water heaters, drinking fountains, hose bibs, floor sinks and the items on the plumbing schedule - **Backflow, testing and closeout:** backflow assemblies, pressure and flow testing, and inspection sign-off ( [backflow prevention](https://legacyplumbingmo.com/commercial/backflow-prevention) ) - **Specialty systems** where the project needs them, including [medical gas](https://legacyplumbingmo.com/services/medical-gas) ## Building Types [Warehouse and light industrial](https://legacyplumbingmo.com/industries/industrial-manufacturing) , [restaurant and food service](https://legacyplumbingmo.com/industries/restaurants-food-service) , [office and tenant finish](https://legacyplumbingmo.com/commercial/tenant-finish) , [multifamily](https://legacyplumbingmo.com/industries/multifamily) , healthcare and dental ( [healthcare](https://legacyplumbingmo.com/industries/healthcare) , [dental](https://legacyplumbingmo.com/industries/dental-office-plumbing) ), and [education](https://legacyplumbingmo.com/industries/education) . ## How We Bid and Deliver - **Bid-spec:** send plans and specs and we deliver a line-item proposal with clear inclusions, exclusions and alternates ( [bid-spec plumbing](https://legacyplumbingmo.com/commercial/bid-spec) ) - **Design-build and design-assist:** we help work out riser layouts, fixture counts and routing early, when changes are cheap ( [design-build](https://legacyplumbingmo.com/commercial/design-build) , [design-assist preconstruction](https://legacyplumbingmo.com/services/design-assist-preconstruction) ) - **Coordination:** we raise conflicts at coordination, not on site, because late changes cost the GC the most. ## Local Conditions and Permitting in O'Fallon Based on City of O'Fallon published information (always confirm current requirements before bid): - The Building Division performs plan review and inspections. The City states that commercial permits are required for any new commercial project, including alterations or additions. - Plumbing work requires a permit, and inspections are scheduled through the City's CitizenServe portal. - The City's adopted ICC codes, including local amendments, can be viewed at [codes.iccsafe.org](https://codes.iccsafe.org) . Confirm the adopted plumbing code edition with the Building Division for your permit set. - Grading, driveways and excavation permits run through the Engineering Department, and stormwater facilities require a maintenance agreement. - Public Works maintains the City's water mains and sewer lines, so tap and tie-in timing should be coordinated early. ## Why Legacy - Local office and crews in O'Fallon. - Underground, rough-in, trim and backflow handled by one plumbing contractor, so one party is responsible for tests and sign-offs. - We stay on after turnover through [service agreements](https://legacyplumbingmo.com/service-agreements) and [commercial service](https://legacyplumbingmo.com/services/service-repair) . ## Service Area [O'Fallon](https://legacyplumbingmo.com/locations/ofallon) plus [St. Peters](https://legacyplumbingmo.com/locations/st-peters) , [St. Charles](https://legacyplumbingmo.com/locations/st-charles) , [Wentzville](https://legacyplumbingmo.com/locations/wentzville) , [Lake Saint Louis](https://legacyplumbingmo.com/service-area/lake-st-louis-mo) , [Dardenne Prairie](https://legacyplumbingmo.com/service-area/dardenne-prairie-mo) , [Cottleville](https://legacyplumbingmo.com/service-area/cottleville-mo) and the rest of [St. Charles County](https://legacyplumbingmo.com/locations/st-charles-county) . ## Request a Bid Send drawings and your bid date through our [contact page](https://legacyplumbingmo.com/contact-us) or see [bid-spec plumbing](https://legacyplumbingmo.com/commercial/bid-spec) . General contractors: see [our page for general contractors](https://legacyplumbingmo.com/general-contractors) . ## Frequently Asked Questions ### Who inspects plumbing on a new commercial building in O'Fallon? The City of O'Fallon Building Division performs plan review and inspections for commercial projects, and inspections are scheduled through its CitizenServe portal. Confirm the adopted plumbing code edition with the Building Division for your permit set. ### Can Legacy bid from bid-spec drawings and also help with design-build? Yes. We price bid-spec projects from plans and specs and also work design-build or design-assist when the owner wants plumbing input before drawings are final. ### Do you only do commercial work? No. Commercial, industrial and new construction are our focus, and we also provide residential service. Residential customers should go to [residential plumbing](https://legacyplumbingmo.com/residential) or [request service](https://legacyplumbingmo.com/request-service) . ### What happens to the plumbing after the building opens? We offer commercial service and preventive maintenance agreements so the same team that built the system can support it. ## Related - [Contact Legacy Plumbing](https://legacyplumbingmo.com/contact-us) - [Company facts](https://legacyplumbingmo.com/company-facts) - [All pages (llms.txt)](https://legacyplumbingmo.com/llms.txt)