Our tenants just moved in to a fully renovated B+ property and during the renovation the gas hot water heater was jarred loose and unknown to us started leaking.

We had a roof leak back in September at our end cap unit which is a coffee shop (retails strip, 9 tenants, building is only 4 years old) and I reported it to our roof warranty company (Carlisle). 

During the thaw, we discovered a major ground water leak in the basement bedroom.

If a faucet is going to leak  you got to fix it.

It's called Cashflow 101 Calculator. iPhone and Android supported.It seriously does all the calculating for you so you can focus on strategy.

Also, are there large air leaks in the house maybe allowing cold drafts in?

If it is just for getting a feel for it if you know someone with an iphone 12 pro, 13 pro or 14 pro (iphone with lidar) you could have them walk the house with an app called polycam.

Did someone tell him that this iPhone thing would not be the new wave and nobody would pay these data fees for their little phone?

Hey William, not sure if this falls under your specific situation, but in Colorado (and other states) there is something known as constructive eviction. essentially its when a tenant notifies a landlord that a habitability issues has arisen and depending on the issue (loss of heating, gas leak) the timeline that the landlord has to fix the issue varies. if the landlord does not fix the issue, Colorado law allows for the tenant to break the lease by constructive eviction. 

Is there a way to download the BP Calculators to the Iphone as an App?