City Sewer to be added

I’m looking at purchasing a park in PA. The park currently operates on a private treatment plant, but the city does plan on hooking it up to their city system at some point in the future. Normally I would think this is great, but the owner has advised me that once they do this, they will be sending a bill for around 100k (or around 2,000$ per lot) for the hook up fee. Is this normal? I haven’t read or seen anything about this. Any insight would be helpful.