I don't endorse any products, and I'm not endorsing Solus Firepits, but the company had a very interesting blog post recently on the legality of firepits around the country.
The message is: if you or your client are thinking about putting one in the yard, make sure you check out your local ordinances first. In some communities, wood-burning firepits or outdoor fireplaces are simply illegal.
The blog post is very interesting. You may read it here.