Bring a large pot of salted water to a rolling boil. Add rotini pasta and cook according to package directions (7-10 minutes) until al dente. Drain and rinse with cold water.

In a skillet over medium-high heat, cook bacon for 8-10 minutes until crispy and golden. Transfer to a paper towel-lined plate to cool and then crumble.

In a mixing bowl, combine mayo, dry ranch seasoning mix, garlic powder, and black pepper. Gradually whisk in milk until creamy.

In a large bowl, combine cooled pasta, crumbled bacon, halved tomatoes, frozen peas, and shredded cheddar cheese. Pour dressing over and toss until well-coated.

Cover with plastic wrap and refrigerate for at least 1 hour before serving.