There's a lot of nuance to that, because "requirements" vary based on building type and other details. And TBH, I'm not 100% up on the latest details even here in NC, as I've been away from the fire service for some time now.

What I can say with some confidence is that sprinklers are widely required in commercial buildings, and I think it's safe to say that's fairly widespread across the US. But even there, I wouldn't say the requirement is totally ubiquitous.

Getting into residential structures is where it gets murkier. For single family homes, I think something like 46 states don't require sprinklers for new construction. For multi-family, and things like dorms, I'm less clear on the details of what is / isn't required around various parts of the country.

> For single family homes, I think something like 46 states don't require sprinklers for new construction.

Also, just to add on here, a number of states have adopted statewide rules prohibiting local codes from requiring sprinklers for new single-family homes.

Oh, I was meaning for multi-family dwellings. I haven't seen them in single family homes either, though it is interesting that requirements are starting to increase there too.

TBH, I just wish there were stricter rules for smoke detectors and equipment in garages. I feel like this is a big gap with the current rules, at least in my state.