Under the Affordable Care Act (ObamaCare), an employer is required to provide the following for breast-feeding mothers who are employees:

• A reasonable break time for an employee to express breast milk for her nursing child for 1 year after the child’s birth each time such employee has need to express the milk;
• A place, other than a bathroom, that is shielded from view and free from intrusion from coworkers and the public, which may be used by an employee to express breast milk.

The employer is not  required to compensate the employee receiving break time for expressing milk for any work time spent for this purpose.

Furthermore, an employer that employees less than 50 employees is not required to provide the above time and facilities to nursing employees:

if such requirements would impose an undue hardship by causing the employer significant difficulty or expense when considered in relation to the size, financial resources, nature, or structure of the employer’s business.”

However, given the amorphous nature of this quoted language, even small employers (i.e., those with fewer than 50 employees), would be well-advised to provide the break time and facilities, if at all possible.

The above requirement can be found in section 4207 of the Affordable Care Act and at 29 USC 208(r)(1) of the Fair Labor Standards Act of 1938.