Packaging Plant Costs

I am looking at a park with a packaging plant and well water. The park is shy of 100 lots. Is there a rule of thumb regarding the costs to run a packaging plant and also water testing/sampling? Also, should I use the 60x factor if the park has a well and packaging plant and does not charge these costs to the tenants?

Does anyone have experience charging tenants for the cost of the packaging plant and well water, and what methodology did you use to allocate those costs?

Thanks, Bob