Hellobee Boards

Not an employment law expert by any means but my guess is it depends on the term of that contract—do they guarantee you employment on those terms for a defined period?

Am I correct in assuming you aren’t in a union?

I’m not in the USA but in New Zealand your employer would be required to offer additional compensation unless the “on call” hours were already covered as part of your salary. But if it’s not written in your contract then I’d imagine they can’t make you do the additional hours.

Agree with @nwm: - Many salaried positions are “at will”. There may be language like this:
Like all other employees, you will be considered an employee at will, and nothing in this letter or any other statement made to you will be deemed to constitute an agreement of employment for any specific period of time. This means that either you or CompanyX may terminate the relationship at any time with or without cause.

(My background is recruiting, not law, btw.) If so I think they can basically tell you whatever they want about changing the required hours, just like they could terminate you without cause (like if they just wanted to downsize). It’s certainly annoying and frustrating, especially if it means you need to look for a new job, but I think they’re within their rights. You may have some leverage if you have, say, extensive training in order to be able to do the job. It’s fairly expensive to find new hires and bring them up to speed, so they likely want to keep you (but again would be at their discretion).

@kiddosc: has a good point. What are your benefits at 31 hours? If you're expected to "be available" 40 hours, seems like you should also be receiving full benefits, if you aren't already.