I have a sulfa allergy. Is if safe to take levaquin?

Yes. There's no relationship between sulfa allergy and being allergic to the class of drugs levaquin is in (floroquinilones). Take as prescribed by your doctor.
Yes. This is not a sulfonamide. The guidelines, however, discourage use of fluoroquinolones because of potential serious side effects. Ask your Dr if you really need an antibiotic. If so, is this the only choice? You neglected to identify the target of the levaquin. Are you sure you are allergic to sulfonamide? Many people are not diagnosed correctly about this.
Levaquin. Levaquin is not a sulfa drug. It belongs to the group of antibiotics called fluoroquinolones. It should be safe to take if you have a history of sulfa allergy.