Houston has no zoning, so there is no zoning map to look up. The answer comes from Chapter 42, from the overlay on your block, and from what the original plat restricted the property to. Enter the address and we will read the City's own layers.
Most people divide their square footage by 3,500 and stop. Frontage, the special minimum lot size overlay on your block, and single family deed restrictions each decide it too, and any one of them can end the split on its own.
Inside the city, City Council can set a minimum lot size for a specific block or neighborhood that overrides the citywide 3,500 square feet (section 42-197). On a 14,000 square foot lot the citywide minimum would allow four lots. A 5,000 square foot overlay on that block cuts it to two, and your deed will not show it.
Inside the city the minimum is 3,500 square feet. In the ETJ it is 5,000 (section 42-181). Both numbers are for a lot with wastewater collection service; a lot on septic follows other rules (section 42-180). In the ETJ, shared driveways are not available, and the reduced building lines under section 42-157 do not apply. Same ordinance, different answers, depending on which side of the line you are on.
Every read queries the City of Houston's own GIS layers rather than a generic parcel database, and it separates what it confirmed from what it could not. Where a layer does not answer, the report says so instead of filling the gap with a default. A confident wrong answer about whether your lot can be split is worse than no answer, because you would act on it.
Private deed restrictions are recorded with the county. We do not read them, and a title report is how you confirm them.