Reliable and Dependable are both positive character traits that can be used to describe a person, animal, or thing. Reliable is the trust that you have for someone or something wherein you know for a fact that they can do a certain task over and over again with the same expectation.
On the other hand, when someone or something is called dependable, they have a personality, quality, or specification that, like reliable, they can do very well, but usually it is someone or something that you look for when you cannot do a certain task.
That is why you become dependent on them to do the task for you. An example of which is you may always rely on your car to bring you to work but you are not necessarily dependent on it.
The words dependable and reliable both refer to the character traits of someone. Reliable describes a person who is competent and consistent when they work. Someone who shows up for their job on time every day and never misses a beat is reliable. The word reliable can also be used to describe a machine, such as an ATM, for example.
You could say that the ATM is more reliable than a teller simply because of their swiftness, and they are also easy to operate. Just like a human being, reliable machines can be trusted to do their work. On the other hand, dependability is a little bit different. Dependable implies a certain amount of loyalty. For example, you could say that you depend on someone for emotional support, or that you can depend on a specific person to visit you in the hospital when you are sick.
Dependable is also a bit more personal because typically, you don’t depend on strangers, but rather, your friends and your family. Dependable people are overall more balanced, as they are reliable in every aspect of their life, including work and family. You could say that dependability is a more attributable character trait.