Yes, you can set a policy on this regarding premium deductions while on leave, unless they signed a waiver disallowing it and set up an agreement on how to pay for it and inform them of consequences when not paid. You can check the DOL site for both Fed and your State for limitations.

Here's a sample verbiage I used in the past:

E. Employee Status and Benefits During Leave

While an employee is on leave, the company will continue the employee's health benefits during the leave period at the same level and under the same conditions as if the employee had continued to work.

If the employee chooses not to return to work for reasons other than a continued serious health condition of the employee or the employee's family member or a circumstance beyond the employee's control, the company will require the employee to reimburse the company the amount it paid for the employee's health insurance premium during the leave period.

Under current company policy, the employee pays a portion of the health care premium. While on paid leave, the employer will continue to make payroll deductions to collect the employee's share of the premium. While on unpaid leave, the employee must continue to make this payment, either in person or by mail. The payment must be received in the Accounting Department by the ______ day of each month. If the payment is more than 30 days late, the employee's health care coverage may be dropped for the duration of the leave.

The employer will provide 15 days' notification prior to the employee's loss of coverage.

If the employee contributes to a life insurance or disability plan, the employer will continue making payroll deductions while the employee is on paid leave. While the employee is on unpaid leave, the employee may request continuation of such benefits and pay his or her portion of the premiums, or the employer may elect to maintain such benefits during the leave and pay the employee's share of the premium payments. If the employee does not continue these payments, the employer may discontinue coverage during the leave. If the employer maintains coverage, the employer may recover the costs incurred for paying the employee's share of any premiums, whether or not the