Final answer:
The EPA assumes electronic or ultrasonic testers are effective at detecting leaks and are also inexpensive and safe for the environment, often employed in various daily applications.
Step-by-step explanation:
Electronic or ultrasonic testers are assumed by the Environmental Protection Agency (EPA) to be effective at detecting leaks. These devices operate by emitting ultrasonic waves and then timing how long it takes for the echoes to return, indicating the presence of a leak or an object. They are often inexpensive to use, and can be found in a variety of applications including automatic camera focusing, door opening systems, home security lights, and automated faucets in public restrooms. The latter helps in reducing the spread of germs and conserving water, thus also deemed safe for the environment. While not explicitly mentioned, ease of operation can be inferred from the widespread use of such technology in everyday devices and facilities.