Usually yes above 4 feet. The residential code corridor cities adopt exempts retaining walls up to 4 feet tall, measured from the bottom of the footing, unless they hold back a surcharge such as a driveway, slope, or building. Taller or loaded walls need a permit and engineered design.
More detail
The 4-foot line comes straight from the International Residential Code: Section R105.2 of the 2021 edition exempts retaining walls not over 4 feet in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge. Sherman adopted the 2021 codes, Denison and McKinney have moved to the 2024 editions, and all three review taller walls through their permit portals, where the design typically arrives sealed by a Texas-licensed engineer. Height is measured from the footing, so a wall showing 3.5 feet above grade with a buried footing can already be over the line. Location adds a second layer in Sherman. The city's engineering manual requires an Easement Use Agreement, on top of the building permit, for any retaining wall inside an easement that is over 3 feet tall or that supports a structure, and it allows walls under 3 feet that support nothing and stay out of the visibility triangles only with the City Engineer's approval. HOAs and lake communities add their own review, and on Lake Texoma the Corps of Engineers prohibits cuts, fills, and terracing on its land altogether. On unincorporated Grayson and Collin county land there is no building permit for a wall, although Collin County issues development permits for ground disturbance and both counties apply floodplain rules where mapped. The permit threshold is not an engineering threshold: a 5-foot wall on county land carries the same soil pressure as one in town, and saturated Blackland clay pushes hard enough to rotate an undersized wall anywhere. The retaining wall drainage post explains what keeps a wall plumb, the drainage FAQ lists the system behind it, the permit guide maps each office, and every retaining wall scope names the permit path for your address.