If you're on the North Side, try the Lone Star Symphonic Band or The Woodlands Concert Band. (The Woodlands group is going to Midwest so you might need to wait until later this year to join that group)
If you're nearer to downtown/central, try Houston Symphonic Band, the Houston Concert Band, the Houston Brass Band, or the Houston Pride band if that's your thing.
If you're on the south side, the Gulf Coast Concert Band is also worth looking into.
If you're WAAAY on the North side, Livingston has had a community band for years - it may be closer than some of the others.