Cost to Basement Bathroom Addition in St. Louis, MO
$6,160–$17,600 in St. Louis
12% below the national average · 0.88x cost multiplier
In St. Louis, a basement bathroom addition runs $6,160 to $17,600 on average — about 12% below what homeowners pay nationwide. The Midwest market's labor costs account for most of the gap, with material pricing and local permitting fees adding to the spread. Use the cost table below to compare budget, mid-range, and premium options side by side.
Cost Breakdown in St. Louis
| Line Item | Low | Mid | High |
|---|---|---|---|
| Cost per bathroom | $3960 | $11000 | $22000 |
| Materials | $2,464 | $5,280 | $12,320 |
| Labor | $3,520 | $6,600 | $10,560 |
| Permits | $528 | $704 | $880 |
| Total | $6,512-12% vs. national avg | $12,584-12% vs. national avg | $25,080-12% vs. national avg |
Budget
Half bath (toilet and sink) added to unfinished basement near existing stack. Basic fixtures, standard tile, and minimal framing.
Mid-Range
Full 3-piece bath (toilet, sink, shower) with below-slab ejector or macerating toilet system, mid-range tile, standard vanity, and proper ventilation.
Premium
Full bath with tile shower, premium fixtures, custom vanity, below-slab plumbing with ejector pump, heated floor, and full exhaust ventilation system.
Material Options
Material prices below are national averages; availability in St. Louis may shift costs slightly.
| Material | Cost/Unit | Best For |
|---|---|---|
| Macerating (Upflush) Toilet System | $700-$1,800 unit only | Budget basement bathroom additions, retrofit situationsNo concrete breaking required, lower upfront cost, relocatable |
| Below-Slab Ejector Pump System | $1,500-$4,000 for pump and pit only | Long-term reliable basement bathrooms, high-use situationsCode-compliant everywhere, gravity-fed to pump, quieter |
| Standard Ceramic Tile | $3-$10/sq ft materials only | Budget to mid-range basement bathroomsAffordable, durable, waterproof, wide selection |
| Luxury Vinyl Tile (LVT) | $3-$8/sq ft materials only | Budget installs, DIY-friendly flooringWarm underfoot, waterproof, easy DIY install |
| Porcelain Tile (Floor and Shower) | $6-$25/sq ft materials only | Premium basement bathrooms, shower surroundsMost durable, low water absorption, premium look |
Other Projects in St. Louis
St. Louis Estimate
Typical Range
$6,160–$17,600
vs. National Average
12% below national
Cost Multiplier
0.88x
Cost Per bathroom
$3960–$22000
Estimates apply St. Louis's 0.88x regional cost multiplier to national averages. Actual bids vary by contractor, project scope, and timing.
See national average costs →