Chick-fil-A has the best food, best customer service, and cleanest bathrooms in American fast food, according to Business Insider readers.

The chain's franchise model helps Chick-fil-A beat out the competition when it comes to service and cleanliness.

Chick-fil-A is the third largest chain in the US by sales, growing revenue by 16.7% in 2018 to reach nearly $10.5 billion.

Visit Business Insider's homepage for more stories.

Chick-fil-A customers are confident that the chain is the best in the business.

44% of people who had visited Chick-fil-A in the last six months said the chain had the best food, far more than customers of any other chain.

71% of people who went to Chick-fil-A in the last six months said Chick-fil-A had the best customer service.

51% of people who visited McDonald's in the last six months said the chain had the best bathrooms. (55% said the brand also had the cleanest restaurants.)

Read more: The 8 fast-food chains with the cleanest restaurants in America, according to customers

We asked 3,000 people who read our fast-food coverage which chains come out on top in all of these categories — and no one chain came close to Chick-fil-A. To avoid penalizing Chick-fil-A and other smaller chains, we only considered responses from people who said they visited a chain in the last six months and who said the brand was the best in a category.

In-N-Out regularly snagged the No. 2 spot in most categories, including best food and cleanest restaurants. But, Chick-fil-A's dominance is clear.

Why is Chick-fil-A thriving in a way other chains cannot imitate?

One thing that sets Chick-fil-A apart from rivals is that franchisees are only allowed to open a single location.

They don't have to pay much — unlike other chains — but the process of getting approved is extremely drawn-out and difficult. Once these franchisees have fought to be a part of the system, they are hands-on in making sure their locations are clean and offering top-notch service, which helps explain Chick-fil-A's high scores.

This model and other aspects of Chick-fil-A's business have helped the chain become one of the most successful in fast food.

The chain is the third largest in the US by sales, growing revenue by 16.7% in 2018 to reach nearly $10.5 billion, according to Nation's Restaurant News. Over the past decade, it has nearly tripled its annual sales.