Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.
In a large mixing bowl, combine the chopped dill pickles, red onion, and celery.
In a separate bowl, whisk together the mayonnaise, sour cream, Dijon mustard, pickle juice, garlic powder, salt, and black pepper until smooth.
Add the cooled pasta to the vegetable mixture, then pour the dressing over the top. Gently toss until everything is well combined.
If using, fold in the fresh dill for added flavor.
Cover the salad and refrigerate for at least 1 hour to allow the flavors to meld.
Serve chilled and enjoy!