Texas Plumbing Code

Adopted Code

Local jurisdictions may amend the state code further. Always confirm with the authority having jurisdiction before submitting for permit.

How the Texas Code Is Organised

Texas does not impose a single plumbing code statewide in the way most states do. State law establishes both the International Plumbing Code and the Uniform Plumbing Code as acceptable, and the operative choice is made by each municipality. The practical consequence is that there is no single Texas table to size from: the applicable document is a local question, resolved per jurisdiction before design starts.

What It Changes About Sizing

The IPC and UPC do not agree on drainage fixture unit values, vent sizing methods or approved materials. Sizing a drain under one and submitting under the other is the single most common cause of rejected plans in Texas, and it is an avoidable one: establishing the adopted code is a phone call to the municipal building department.

Licensing in Texas

Licensing runs the opposite way — fully centralised. The Texas State Board of Plumbing Examiners function is administered through the Texas Department of Licensing and Regulation, and licences are statewide: tradesman plumber, journeyman, master, plus endorsements for medical gas and multipurpose residential fire sprinkler. So a licence valid in Houston is valid in Amarillo while the code you must satisfy may differ between them.

Cities That Do Something Different

Because adoption is municipal, the carve-outs are the norm rather than the exception. Large cities publish their own amendment schedules on top of whichever model code they adopt. Unincorporated county areas may have no municipal plumbing adoption at all — in which case state licensing law still governs who may perform the work, even where no local code review applies.

What Out-of-State Contractors Get Wrong in Texas

1. 1Designing before confirming which model code the municipality enforces. In Texas that is not a formality; the answer changes the tables.
2. 2Assuming a statewide code exists because licensing is statewide. The two are decoupled here in a way they are not in most states.
3. 3Treating unincorporated areas as unregulated. Local plan review may be absent, but state licensing requirements are not.
4. 4Carrying a design across a city boundary unchanged. Neighbouring Texas cities can be on different model codes.

Texas in Practice

Our sizing calculators state the edition and table they use: pipe sizing, drainage slope, gas line sizing. Check them against the TX edition in force before relying on a result.