Here in so cal your free to rent what used to be the home of drag boat racing, Marine Stadium...right behind Bako, from the city and do with it what you please. As long as you comply to the rules they lay down.
Ski Land was the last great privately owned body of water that held races, it was open until what...the mid to late 80's? I can remember my last trip there was in '82 I think. Is that property all developed now? I haven't been there in years.