NIAGARA FALLS, N.Y. (AP) _ Pete Zito grossed only $31.80 on The Inferno's first night, but he's optimistic New York's new drinking age of 21 will send youths rushing to his no-alcohol nightclub.

Zito, a musician and restaurateur, feels that with the drinking age rising from 19 to 21 Sunday, teen-agers will need a place to go, and he is betting $150,000 that he is in the vanguard of a trend.

''I think places like this will be popping up in the next few years,'' Zito said leaning over the counter of his club. ''Even bars themselves may be converting.''

''People can have fun without getting sloshed,'' he said. ''Especially when you look at all the people who are living more healthy lives, who go to health clubs, people like that will come here.''

The Inferno - named, its owner said, to project a hot-spot image in a former catering hall he renovated - is located in a residential area north of the famous falls. Zito estimates that 5,000 to 8,000 teen-agers live within walking or driving distance of the club and that if he can attract 100 people a night, he can break even.

''Money is the name of the game. Right now I'm pretty squeezed,'' Zito admitted after the Inferno's first four weekend nights. ''But I'm committed to this. I can stay open as long as my other businesses can support it.''

The Inferno, which can accommodate 300 people at a time, has a dance floor and a $25,000 sound system for live or recorded music, as well as a pool table, fireplace and video games.

It offers fruity concoctions called The Hulkster, T-N-T and a Brown Ape, among others, along with snacks. If business picks up, Zito said, he plans to open a kitchen so he can serve a menu of fast food.

''It's the same nightclub atmosphere, with dancing, things to eat, people to talk to - that's the key thing, to get the people in here to talk to,'' he said. ''I want to get the message out they don't have to drink to have a good time.''

A dress code, a $3 cover charge - which permits two return visits - and $2 drinks should attract a relatively trouble-free clientele, Zito said, but he admits he will have to deal with fights, people who have been drinking somewhere else, and perhaps drugs as well.

''We can't be detectives and frisk them when they come in or give them polygraphs,'' he said, but alcohol will be confiscated when it is spotted. ''We might have a garbage can full of booze at the end of the night, but that's all I need. This is not going to be a speak-easy. ... With an investment like this you can't chance an image we're trying to establish, especially at the start.''