We do however allow the tenants to use the water to maintain the landscaping, their flower beds and vegetable gardens.Here are actual numbers of usage by 100 Cu Ft per read date for this past year.1/8/16 - 54 cu ft11/5/15 - 49 cu ft9/7/15 - 60 cu ft7/6/15 - 55 cu ft5/6/15 - 49 cu ft3/3/15 - 53 cu ftSo, in our experience it is quite manageable for us to pay for the water.

I found that the Kansas City Water Dept has a graph of the last 90 days' usage. 

Then in the lease agreement state that based on the usage by the tenants, the heating costs will be reevaluated every 6 months and adjusted if necessary. 

Sift through the list and then adapt an excel spreadsheet to your specific uses.RE: Specific play-by-play excel usage...that will take awhile to type out here.

Based on the average utilities usage for the property, we set an amount the tenant will pre-pay into the utilities account at the start of each month.  

You should also be monitoring the bills from the water company to see if there are any spikes in usage. 

Their usage = their expense!

If all of these are true, your business usage does NOT affect your gain/loss calculations

do you know PHP and usage of third party APIs over REST?

...will credit for my usage of utilities.I might be making this more complicated than it should be.