Critical — FL Slab-on-Grade Foundation
FL homes are built on concrete slab foundations — there is no basement or crawl space. ALL drain lines must be installed BEFORE the slab is poured. Mistakes in underground plumbing require saw-cutting the slab to fix. The rough-in inspection MUST pass before concrete is poured.
FL New Construction Cost Context
Plumbing is typically 8–15% of total new home construction cost in FL. On a $350,000 build, expect $28,000–52,500 for all plumbing. On a $500,000 build, budget $40,000–75,000. FL has strict licensing requirements (FS 489) — all plumbing work must be performed by a licensed plumbing contractor.
FL New Construction Plumbing Overview
New construction plumbing happens in two phases: rough-in (before walls and slab are closed) and trim-out (after construction is complete). Because FL builds on concrete slabs with no basement access, all underground drain lines must be precisely located before the foundation is poured.
The 5 FL New Construction Plumbing Phases
- Underground Rough-In — All drain/supply lines installed before slab pour. Inspection required and must pass before concrete pour. Errors require saw-cutting to repair.
- Slab Pour — Concrete poured over drain lines; underground plumbing now permanently inaccessible. Errors at this stage cost $3,000–8,000+ per repair.
- Framing Rough-In (In-Wall) — Supply lines (PEX) and vent pipes installed inside walls. Second inspection required before drywall. Pipe penetrations fire-blocked per FL Building Code.
- Trim-Out (Fixture Installation) — Toilets, faucets, shower valves, water heater, dishwasher, laundry, appliance connections installed after drywall/finish.
- Final Inspection & Certificate of Occupancy — Building dept inspects all fixtures, pressure-tests system, verifies code compliance. CO cannot issue until all plumbing inspections pass.
FL vs. National: Key Differences
- No Basement or Crawlspace — FL homes are 100% slab-on-grade. Zero access after slab pour.
- PEX Is Dominant & Preferred — FL's chloramine-treated municipal water and hard water cause premature copper corrosion. PEX-A and PEX-B are the FL standard.
- FL Building Code Chapter 24 — FL adopted 2020 FBC Plumbing edition (pipe sizing, vents, trap distances, fixture units, water heaters).
- Mandatory Backflow Prevention — Required on all irrigation connections, pool fill lines, cross-connection points (FBC 608).
FL Plumbing Material Comparison
| Material | Use | FL Pros | FL Cons | Cost |
|---|---|---|---|---|
| PEX-A | Supply | Flexible, chloramine-resistant, freeze-tolerant, expandable fittings | Cannot be exposed to UV (in-wall only) | $$ |
| PEX-B | Supply | Less expensive, widely used in FL | Less flexible, crimp fittings | $ |
| CPVC | Supply | UV resistant, rigid, above-slab use | Can crack in FL freeze events | $ |
| PVC / ABS | Drain/waste/vent | FL standard for DWV, cost-effective, durable | None — standard choice | $ |
| Copper | Supply | 50+ yr track record, accepted everywhere | FL chloramine water causes pitting, expensive | $$$ |
| PEX-AL-PEX | Supply | Less thermal expansion, good for long hot runs | Less common in FL, specific fittings | $$ |
PEX-A/B recommended for FL new construction supply lines.
FL Statutory Warranty — FS 553.84 & Homebuilder Warranty Act
- 1-Year: Workmanship defects — all visible/accessible plumbing work
- 2-Year: Mechanical systems — plumbing, electrical, HVAC
- 10-Year: Structural defects affecting habitability
Keep all inspection reports, as-built drawings, and written warranties. FL allows private right of action for code violations under FS 553.84.
FL New Construction Plumbing Permit Checklist
| Phase | Permit | Who Pulls It | Inspection Trigger |
|---|---|---|---|
| Underground rough-in | Yes | Licensed plumbing contractor | Before slab pour |
| Framing rough-in (in-wall) | Yes | Licensed plumbing contractor | Before drywall |
| Gas piping | Yes (separate gas permit) | Plumbing or gas contractor | Before drywall |
| Water heater | Yes (typically included) | Same plumbing contractor | At trim-out |
| Final plumbing inspection | Yes | Building department | Before CO issued |
| Irrigation backflow | Yes | Licensed contractor | Separate inspection |
| Sewer connection | Yes | Utility coordination | Before slab |
| Septic system (if applicable) | Yes (FL DOH) | Licensed septic contractor | Separate DOH process |
FL New Construction Builder Red Flags
- Uses unlicensed plumbing subcontractors (verify on FL DBPR)
- Cannot provide inspection reports for underground rough-in on past projects
- Specifies copper supply lines without explanation (PEX-A/B usually better for FL)
- Cannot provide as-built plumbing drawings after completion
- Proposes skipping backflow preventer on irrigation (FL code violation)
- Proposes skipping expansion tank on closed water heater system (FL code requirement)
Document Checklist — Keep These After Closing
- All building dept inspection reports (underground, in-wall, final)
- As-built plumbing drawings with pipe locations/sizes
- Plumbing contractor's FL FS 489 license copy and insurance certificate
- Written warranty per FL FS 553.84 (1-yr / 2-yr / 10-yr)
- Water heater manufacturer warranty and serial number
- Backflow preventer inspection certificates