Legal Question in Employment Law in California

If you mean community service hours away from work, and not simply unpaid OT at work, yes they can. Law firms, charities and others do it frequently.

The employer is entitled to set and change hours, duties, titles, compensation, benefits, leaves, vacations, holidays, policies, rules, etc. just not retroactively. In general, unless an employee is civil service, in a union, or has a written employment contract, they are an 'at will' employee that can be disciplined or fired any time for any reason, with or without �cause�, explanation or notice, other than for illegal discrimination, harassment or retaliation under the ADA disability, Civil Rights [age, race, sex, ethnic, religion, pregnancy, etc], Whistle-blower, or similar statutes. The employee's goal should be to keep the employer happy.