A Perth homeowner claims his local council has invaded his privacy by using "spy in the sky" technology to identify an unapproved swimming pool.

Ryan said he had received a notice from the City of Belmont that an illegal pool had been detected in his backyard.

Belmont resident Ryan and his now empty pool after city "eye-in-the-sky" technology pinpointed his unapproved structure.

"I feel like I'm living in some kind of nanny state," he said.

Six months earlier, he and his partner received another notice from the city threatening a $15,000 fine for excessive noise.