Missouri (MO) Plumbing Code & Permit Rules
International Plumbing Code (2018) · Updated 2026-05-31
Data: State plumbing boards, ICC, IAPMO, EPA Last verified: 2026-05-31
Missouri requires licensed plumbers for most plumbing work and mandates annual backflow testing. These regulations help protect water quality but mean higher costs for homeowners compared to states that allow DIY work.
Plumbing Code
Missouri follows the International Plumbing Code (2018 edition).
Some areas may use UPC
Key Regulations
| Regulation | Status | Details |
|---|---|---|
| Plumbing Code | IPC (2018) | International Plumbing Code |
| Homeowner DIY | Not allowed | Licensed plumber required |
| Water Heater Permit | Required | |
| Backflow Testing | Annual, required | |
| Seismic Strapping | Not required | Water heater restraint |
DIY Plumbing in Missouri
Missouri requires a licensed plumber for most plumbing work. Licensed plumber required
While this increases costs, it ensures:
- Work meets current code requirements
- Proper permitting and inspection
- Warranty and liability protection
- Safe connections to water and sewer systems
Backflow Prevention
Missouri requires annual backflow testing to protect the public water supply from contamination. Testing must be performed by a Certified tester.
Non-compliance penalty: Water service may be shut off if testing is not completed on schedule.
Water Conservation Requirements
Missouri follows federal water conservation standards. Federal minimums apply
Lead Service Line Replacement
Missouri has an active lead service line replacement program. Following EPA Lead and Copper Rule 2021
Data Sources
- Missouri state plumbing board and licensing agency
- International Code Council (ICC)
- IAPMO
- EPA Safe Drinking Water Act
Updated as regulations change.
Need a licensed plumber in Missouri?
Plumbing regulations vary by city. Connect with a licensed professional who knows your local code requirements.
Find a Licensed Plumber →Frequently Asked Questions
What plumbing code does Missouri follow?
Missouri follows the International Plumbing Code (2018 edition).
Can I do my own plumbing work in Missouri?
No, Missouri requires a licensed plumber for most plumbing work.
Do I need a permit to replace a water heater in Missouri?
Yes, Missouri requires a permit for water heater replacement. A licensed plumber is required for the installation.
Is backflow testing required in Missouri?
Yes, Missouri requires annual backflow testing.
Does Missouri require seismic strapping for water heaters?
No, Missouri does not require seismic strapping for water heaters. However, they remain a prudent option in areas with seismic activity.