Should I tell my employer about my arrest?

Several things bear on it.

Do you have a reporting obligation? Some employment contracts, licensing requirements, and industry regulations require disclosure of an arrest or charge — sometimes on a short deadline. Where an obligation exists, failing to report is frequently worse than the underlying matter, because it goes to candor.

Will they find out? Ongoing background monitoring is common in some industries. Arrests are public record. Local news covers some cases.

What's the disposition likely to be? Where a case is likely to resolve favorably and quickly, and there's no obligation to report, waiting may be reasonable.

What's the relationship? Some employers respond better to being told directly than to learning later.

What not to do: discuss the facts of the case with an employer. Whatever you say can be obtained. If you disclose, disclose the existence of the matter and that it's being handled by counsel — nothing about what happened.