Do I need a plumbing permit in Missouri?

In Missouri it depends on the size of the job. Permits are issued locally, so the answer comes from your Missouri city or county rather than a single statewide rule. Of the 2 Missouri jurisdictions we have verified for plumbing work, 0 require a permit outright, 2 depend on the size or scope of the job, and 0 require none.

Is there a plumbing permit exemption in Missouri?

2 of the 2 Missouri jurisdictions we cover set a threshold rather than a flat rule, so the same job can be exempt in one Missouri county and permitted in the next. The table above lists each Missouri jurisdiction's published threshold in its own words, with the source and the date we verified it.

Missouri

Do you need a plumbing permit in Missouri?

By Mario Bailey Last checked 16 Aug 2026

Always required: 0; of 2 jurisdictions
Conditional: 2; depends on size or scope
Not required: 0; exempt outright

Plumbing Permit rules nationwide, beyond Missouri.

A plumber tightens a fitting on water supply pipes

Requirements and size thresholds for plumbing permits vary by locality. The table below compares what each Missouri county or city requires. Always confirm with the local office before starting.

Comparing states? See plumbing permit rules across every locality we cover.

The application steps and inspection sequence for plumbing permits come from the model code rather than from Missouri law, so they read the same wherever you build. We keep that walkthrough in one place: how a plumbing permit application and its inspections work, start to finish. What changes between Missouri jurisdictions is below: who requires a permit, what they charge, and which office you file with.

Swipe sideways to see thresholds and confidence.

Locality	Permit required?	Typical threshold	Confidence
Kansas City	Conditional	Before installing, altering, repairing or replacing waste, vent, water or gas piping...	Confirmed on official page
St. Louis	Conditional	Before any plumbing, drainlaying or process drainage work, any connection to a sewer...	From an official source
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Common questions about plumbing permits in Missouri

Do I need a plumbing permit in Missouri?: In Missouri it depends on the size of the job. Permits are issued locally, so the answer comes from your Missouri city or county rather than a single statewide rule. Of the 2 Missouri jurisdictions we have verified for plumbing work, 0 require a permit outright, 2 depend on the size or scope of the job, and 0 require none.
Is there a plumbing permit exemption in Missouri?: 2 of the 2 Missouri jurisdictions we cover set a threshold rather than a flat rule, so the same job can be exempt in one Missouri county and permitted in the next. The table above lists each Missouri jurisdiction's published threshold in its own words, with the source and the date we verified it.

Do you need a plumbing permit in Missouri?

Common questions about plumbing permits in Missouri

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