[Svartalfiar]

The county argued that by both lots being owned by the same people and their use of the lots as one lot, they in fact had ‘merged’ the lots into one and were no longer grandfathered for developing both lots.

But they didn't combine them. Legally they were still two separate lots. Tax-wise they were separate.

If I buy a car and let my kid drive it to school and work, and he pays for fuel and basic maintenance while he uses it, does that make him the legal owner of the car? Not at all. Just because something is used in one manner doesn't legally turn it into something else.

[TexasGator]

“Just because something is used in one manner doesn’t legally turn it into something else. “

Google ‘adverse possession’.

[TexasGator]

“But they didn’t combine them. Legally they were still two separate lots. “

Not according to the local zoning laws.