O'Fallon, MO · 2026 Cost Guide
How Much Does a Bathroom Addition Cost in O'Fallon?
Adding a bathroom is one of the highest-value improvements, especially going from 1 to 2 baths. In O'Fallon, labor rates run $65–$120/hr — below the national average — which is factored into all estimates on this page.
The wide price range reflects major differences in project scope, materials, and the age of your home. A cosmetic refresh costs far less than a full renovation, and O'Fallon's specific market conditions affect contractor pricing year-round.
| Cost Factor | Typical Range | Impact on Price |
| Full vs half bath | $10,000–$30,000 difference | High |
| Plumbing location | $2,000–$8,000 | High |
| Square footage | Scales linearly | High |
| Permits | $500–$2,000 | Medium |
| Labor | $70–$130/hr | High |
Does it increase value?
Adding a full bath can increase value by 5–10%.
Best location?
Near existing plumbing — converting a closet is most cost-effective.
How long does it take?
6–12 weeks.
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