Merely making du/tri/quad-plexes no longer explicitly illegal doesn't actually make them legal. Or, under discussion here, merely making small lots no longer explicitly illegal doesn't, on its own, actually make them legal.

Texas' new maximum minimum lot size bill (maximum allowable minimum lot size will be 1,400 square feet) attempts to be comprehensive by addressing

maximum allowable minimum lot width - 20'

maximum allowable minimum lot depth - 60'

maximum allowable minimum setbacks

-------Front and Rear - 10'

-------Side - 5'

maximum allowable minimum parking - 1 per unit

-------can not be required to be covered

-------additional parking can not be required offsite

maximum allowable permeable surface requirement - 30%

Minimum maximum allowable floors - 3 floors.

Why does this comprehensiveness matter? We can see it even within this law.

Take the 20' width by 60' depth (this would be 1,200 square feet which is less than the 1,400 in the law)

with 10' front and back setbacks and 5' side setbacks

the remaining buildable plate in the center of the lot is 10' x 40', which is functionally unbuildable (almost no one wants a 10' wide housing unit). If municipalities implement these setback the functional minimum lot size is in reality 30' x 60', or 1,800 sf (400 sf larger than the intention of this law) to leave a 20' x 40' function floor plate.

Of course this is still better than if they still allowed the just as standard 25' front, 15' sides, or even allowed the municipalities to enlarge whatever they currently to implicitly continue to require the standard 5,000, 7,500, 10,000 sf, or larger lots.