I would watch some classes first of all at various times and different days or evenings. If all you see being taught and coached is MMA type fighting and technique and people training for that without the instructor ever addressing any changes to things based on a street or self-defense situation then that is a good indication right there. Take something like shimmying or shrimping while on your back on the mat; that's a basic skill in BJJ and is easy to do on a mat where your body slides some. Doing it on pavement in street clothes though is a lot different and a lot more difficult and painful so your technique with this better be really good.

While there are some things that directly carry over to application in the street there are some things that don't or that have to be modified. If that second part is not being addressed and taught in the classes like in the example that I mention then that's a good indication that its the sport style and fighting style being taught and emphasized. In a school where they teach both the instructor will identify and point out those aspects and teach those training such things when applicable and drill on both.

Also talk to some of those training there and ask them why they chose that place instead of another and are they happy with the training they are getting. If its a place that is dominated by people who say they want to be fighters or learn how to fight in the cage then that also can create an atmosphere where that dominates things and is taught.

Lastly both gi and no gi approaches should be addressed and taught and students learning no gi. Street clothes are much different and more flimsy than a gi and so in a lot of self-defense and street applications you can't rely on using your own clothing or that of your opponent's. You want a place that will teach no gi approaches and technique as well as the street or self-defense application so that you have the fullest understanding of things and the best skills for self-defense and the street and don't have to always rely on a gi.

As someone with same goals, you really won't find a mma place that really focuses on street defense. Our gym worked with ground and pound and everything, but we didn't have to defend against eye pokes, groin strikes, knees or kicks to the head while on the ground, and etc. We didn't do any weapon drills, multiple opponents, grappling with clothes grips or counter to clothes grips, and etc. I had to pretty much go solo training on much of these other aspects or try to pick up the skills from other arts and try to apply it in class.

Ask them what time should I know about class .

you wont learn real BJJ in less it is from the Gracie family...if it is MMA BJJ they will not train you in none sport based BJJ... try to see if there is any BJJ schools that don't do MMA at all.. BJJ should be self defense first sport second, even Gracie family has said they want students to learn to protect them selves.. since you can lose a lot of the techniques Helo came up with... if doesn't work try judo or Jiu Jitsu that is not also in MMA... most MMA schools are all sports based not all some of top programs that train pro fighters have great teachers... but there is less of them MMA has Mcdojo's just like any other martial art...

Just be honest about your goals. Ask if they show both the sport side and the self defense side of Jiu Jitsu. I know that my gym does, and I believe most MMA gyms would because defending against punches on the ground is important in MMA, but just ask politely. The teachers should be more than happy to help you. Newcomers always have questions and they know that.

I am going visit a mma gym tomorrow and I have questions and concerns but I'm afraid I'll come out wrong. Most concern is Brazilian jiu jitstu. I'm tired of going to gyms that don't show how to defend punches off your back. I don't want to practice sport because I'm not planning to compete. I want to practice for street defense. How can I explain that to them? I know sport jiu jitsu is very different from street jiu jitsu.