Do you legally have to tell people you have CCTV?

Do you legally have to tell people you have CCTV depends on location, whether system is residential or commercial, and whether audio is recorded. In United States, for residential CCTV on your own property, there is generally no federal law requiring you to post signs that you have video only surveillance, you can record your own property including front yard and driveway without telling visitors, though it is good practice to post signs as deterrent. For businesses, many states do not require signage for video only, but some states and cities require notice, and best practice is to post visible signs stating premises under video surveillance. For workplaces, many states require employers to provide notice of video surveillance to employees via handbook or posted notice. If CCTV includes audio recording, laws are stricter, many states require all party consent and you must inform people that audio is being recorded. In European Union under GDPR, you generally must inform people with signage stating CCTV in operation, purpose, and contact details. In UK, ICO requires clear signage for CCTV that captures public areas. For doorbell cameras, no signage required but courtesy is appreciated. Always check state laws and consult attorney, posting signs helps avoid legal issues.