San Antonio, TX Noise Ordinances: Vehicle Noise (2026)

Sec. 21-54 targets car stereos and other vehicle-mounted sound equipment specifically: operating a radio, stereo receiver, CD player, cassette player or similar amplified device in a vehicle, in a public or private place, is unlawful if it can be heard from 30 feet or more away, or if it causes anyone outside the vehicle to feel the accompanying vibration. Unlike many other noise offenses in this division, Sec. 21-54 states plainly that 'a culpable mental state is not necessary to constitute a violation,' meaning intent or carelessness makes no difference to liability.

A separate provision, Sec. 21-52(a)(5), addresses engine and exhaust noise rather than stereos: it is a noise nuisance to discharge exhaust from a steam engine, stationary internal combustion engine, automobile, motorcycle or other motor vehicle or boat into the open air except through a muffler or similar device that prevents loud or explosive noise, which reaches straight-piped exhausts and cars with removed or defective mufflers. Sec. 21-55(3) narrows the exhaust rule somewhat: it exempts sound produced by a vehicle's motor while the vehicle is actually moving on a public right-of-way, public waterway, airport runway or railway from the noise-nuisance division generally, so the muffler standard is aimed chiefly at parked, idling or stationary vehicles rather than passing traffic noise.

Both rules fall under the division's shared enforcement and penalty structure: the director can issue an administrative stop order under Sec. 21-57(a), and violations are prosecuted as Class C misdemeanors under Sec. 21-58.