New home plumbing installation happens in three phases: underground rough-in before the slab is poured, top-out after framing, and finish after drywall and flooring are complete. Each phase requires city inspection in Abilene before the next phase of construction can proceed. Understanding this process helps homeowners and builders plan timelines, coordinate trades, and avoid expensive change orders.
Phase 1: Underground Rough-In
The underground rough-in is the first and most critical phase. Before any concrete is poured, the plumber installs all sewer drain lines, water supply lines, and any plumbing that will be encased in the slab. These pipes are laid out according to the floor plan, with drain lines sloped at the correct grade — typically one-quarter inch per foot — to ensure gravity carries wastewater to the sewer or septic system. Any mistakes at this stage are extremely expensive to fix once concrete is poured over them.
Slab Plumbing for Abilene Homes
For slab-on-grade construction, which is the standard in Abilene and most of the Big Country, the sewer lines are typically 3-inch and 4-inch PVC pipe routed through trenches cut in the prepared grade. Water supply lines are run through the slab in protective sleeves or are stubbed up through the slab at fixture locations. The main sewer line connects to the city sewer tap or runs to the septic tank, depending on the property location. Proper bedding and backfill around the pipes prevents settling that can cause joints to separate later.
The Under-Slab Inspection
After the underground plumbing is installed and before the concrete is poured, the city of Abilene requires a plumbing inspection. The inspector verifies that all drain lines are properly sloped, supported, and connected, that cleanouts are accessible, and that the installation meets the current plumbing code. This inspection must pass before the general contractor can schedule the concrete pour. Failing this inspection delays the entire project.
Phase 2: Top-Out After Framing
The top-out phase happens after the house is framed but before insulation and drywall are installed. During this phase, the plumber installs all supply lines to fixture locations, runs drain and vent pipes through the walls and up through the roof, installs shower valves and tub drains, and connects gas lines for the water heater, furnace, stove, and dryer. Vent pipes are essential — they allow air into the drain system so water flows smoothly and prevent sewer gas from entering the home through drain traps.
Pipe Support and Freeze Protection
Proper pipe support is critical during top-out. Supply lines and drain pipes must be secured with appropriate hangers and straps at code-required intervals to prevent sagging, movement, and noise. Pipes running through exterior walls or attic spaces in Abilene need insulation to prevent freezing during winter cold snaps. While Big Country winters are generally mild, temperatures can drop into the teens during ice storms and arctic fronts, and uninsulated pipes in exposed locations are at serious risk.
The Rough-In Inspection
Another city inspection is required after the top-out is complete. The inspector verifies proper pipe sizing, slope on horizontal drain runs, vent pipe termination through the roof, gas line installation, and compliance with code requirements for fixture spacing and access. Like the underground inspection, this must pass before the builder can close up walls with insulation and drywall.
Phase 3: Finish and Final Connections
The finish phase is the final step. After drywall, paint, tile, flooring, and countertops are installed, the plumber returns to mount and connect all fixtures — toilets, sinks, faucets, shower heads and trim, bathtub spouts, the water heater, garbage disposal, dishwasher drain, and any other appliance connections. The plumber also installs shut-off valves at every fixture, sets the water heater temperature, and tests every fixture and connection for leaks.
Total Quality Plumbing provides complete new construction plumbing for custom and standard floor plans throughout Abilene and the Big Country. Licensed master plumber Jacob Gonzalez (TMPL #44777) personally oversees every new build to ensure code compliance at every phase and a plumbing system that performs reliably for decades. Call (325) 266-4887 to discuss your new home project.