In Texas, who is responsible for making sure the site drains properly?

Usually the buyer or site owner, unless a contract says otherwise. Texas manufactured housing rules (the 2004 TDHCA version reviewed here) put site drainage on the purchaser and tell installers not to install unless the grade slopes away from the home or another approved method keeps surface runoff from flowing under it. For industrialized (modular) homes, the Texas Department of Licensing and Regulation says the builder must make sure water drains away on all sides and that subcontractors do nothing to hinder it, while also warning owners that later changes to drainage can cause foundation damage. Before delivery, get grading, gutters and any swales sorted out in writing with your site contractor, and keep landscaping from blocking the flow afterward.

Check your local rule. This varies by state, county or city. Your permitting office has the final word; the official lookup pages below show you who that is.

Sources

• Manufactured Housing Rules (effective Sept. 26, 2004)Texas Department of Housing and Community Affairs
• IHB Technical Bulletin TB 10-01: Foundations on Expansive SoilsTexas Department of Licensing and Regulation