I would echo @Ryan Murdock ... Our second park was a turnaround project that we purchased at a bargain cap rate but where we were going to need to replace all the water and sewer lines in order for the city to agree to let us get all the tenants on direct bill with the city (initially it was one master meter paid for by us, about $5-$6,000 per month, crazy leaks, terrible). So the project was also in the dollar zip code Ryan mentioned, but the way we looked at it was the payback period was manageable since we would be saving ~$60,000 per year in water expense. Took a lot of time, money, patience. But in the end we believed it would be worth it.
Another thing to consider is how hard it is to manage a project like unless you are there every day, or every week (which I was not). Very few contractors are going to work like you are over their shoulder, unless you are. This could start out as a qualitative factor, but can quickly become a quantitative factor.
Lastly, I would suggest having many many discussions with the city or the county about this proposed project. Talk to the water people, talk to the sewer people, talk to the planning people. Get to know them well. It will benefit you.
Good luck.