Building permits, zoning and septic rules in Matagorda County, Texas

Unincorporated Matagorda County requires a building permit for structures of any size or improvements in flood and non-flood areas, including manufactured and relocated homes, barns, workshops, RV covers, carports, sheds, additions and remodels; an RV itself is listed when placed in a flood zone¹. The county Environmental Health Department handles county building permits, and commercial plans need Fire Marshal sign-off¹. Inside Bay City, the city handles its own building permits, including permits before moving a house; county Environmental Health remains the OSSF septic-permit authority^4,8. Matagorda County adopted the 2021 International Fire Code on May 4, 2026; we could not confirm comprehensive county building, residential, plumbing, mechanical or electrical codes⁹. Ask Environmental Health which site inspections apply, because no universal inspection schedule was confirmed¹⁰.

Matagorda County Environmental Health Department handles county building permits at 979-244-2717, First Floor, 2200 7th Street, Bay City, Texas 77414¹. Before beginning a project, obtain a 911 address from Matagorda County 911 Addressing/Emergency Management at 1801 Seventh Street, (Rear Entrance), Bay City, TX 77414, phone (979)323-0707¹. For a dwelling, have the septic installer obtain the septic permit first, or provide the MUD district’s sewer-connection letter¹. The schedule effective May 1, 2022 lists a $100 building-permit fee and $70 for an RV or 100-square-foot storage building in a flood zone; confirm current fees with Environmental Health¹¹. We could not confirm a complete application checklist or review timeline; ask Environmental Health before scheduling construction¹.

Unincorporated Matagorda County has no county zoning ordinance, so county zoning does not set minimum dwelling size, setbacks, lot coverage, building height or occupancy rules for RVs, tiny homes and accessory dwellings². Palacios has city zoning, while Bay City has airport hazard and compatible-land-use zoning; the airport rules do not establish the full extent of Bay City’s general zoning^3,12,13. County Environmental Health administers OSSF septic permits, and Palacios additionally requires a petition to and approval of the city council for private septic systems^4,5. Matagorda County also administers subdivision regulations, but we could not confirm their detailed standards and exceptions; ask Environmental Health before dividing land⁶.

Matagorda County requires a septic permit for every on-site sewage facility regardless of lot size or acreage, with Environmental Health administering county and state OSSF rules⁴. Owner installation is allowed only when the owner is also a Registered Installer; we could not confirm a general building owner-builder exemption⁴. Septic permit fees include inspection services and a license to operate, and an approved maintenance company must perform testing and reporting; ask Environmental Health for inspection stages and any sale or transfer requirements, which we could not confirm¹⁴. The schedule effective May 1, 2022 lists $200 for non-commercial septic permits, $250 for commercial septic permits and $100 for re-inspection; confirm current fees¹¹. The county requires 1 acre for a well and septic system together, with separation between the well and septic tank lines¹. Only about 4.1% of county land is rated without severe limitations for a conventional drain field, making an early site evaluation useful⁷.

An RV in a Matagorda County flood zone needs a building permit; manufactured homes, relocated homes, RV covers and other structures or improvements are covered in both flood and non-flood areas¹. Flood-zone fill dirt also needs a permit, and repairs or improvements reaching 50% of a structure’s appraised value can require elevation, relocation or demolition¹. An off-grid setup still needs permitted wastewater disposal: every OSSF requires a septic permit, installation requires a Registered Installer, and an approved maintenance company must perform testing and reporting⁴. If public or community water is unavailable, the county requires a registered well; contact the Matagorda County Ground Water Conservation District at (979)323-9170¹.

1. Get the parcel's 911 address from Matagorda County 911 Addressing/Emergency Management before beginning the project¹.
2. If public or community water is unavailable, arrange a registered well through the Matagorda County Ground Water Conservation District¹.
3. Hire a Registered Installer and obtain the septic permit before seeking a dwelling building permit, or obtain the required MUD sewer-connection letter¹.
4. Confirm flood-zone status and include any required floodplain or substantial-improvement documentation; fill dirt in a flood zone also needs a permit¹.
5. Apply to Environmental Health for the building permit, confirm the current fee and ask for the application checklist, review timing and inspection plan^1,10,11.
6. For a county-road driveway or culvert, ask the county commissioner for a work order and provide the physical address; for a state highway or farm-to-market road, contact TxDOT¹.

All county land is at a 15% slope or less, while only about 4.1% is rated without severe limitations for a conventional drain field⁷. A county-road driveway or culvert needs a commissioner's work order and a physical site address, while state-highway and farm-to-market access goes through TxDOT¹. If public or community water is unavailable, the county directs the buyer to register a well through the Matagorda County Ground Water Conservation District¹. The nearest city of 100,000 or more is about 57 miles from the county center, and population density is about 33.3 people per square mile⁷. For carrying costs, the effective property-tax rate is about 1.3% and the median annual bill is about $2,035⁷.