Municipal Utility Districts
Many Waller County Subdivisions Are Inside a MUD
A Municipal Utility District — called a MUD — is a small local government that provides water, sewer, and drainage to a subdivision, and it adds its own tax rate on top of county and school taxes.
Waller County has many MUDs, especially in areas near Katy and in fast-growing unincorporated zones. A MUD is created to pay for roads, water lines, and drainage when a developer builds outside city limits. It issues bonds and then collects taxes from property owners to pay them off.
If your address is in a MUD, you will see a separate MUD tax line on your bill. The rate varies by district — some are higher than others. Before buying, look up whether the property is in a MUD and check its current tax rate and any outstanding bond debt. The Texas Commission on Environmental Quality (TCEQ) keeps an official map of all water districts in the state.
Source to confirm: TCEQ — Water Districts Map Viewer