There are large fluctuations between single zip codes (some zips having A/B and as D/F sections within a single zip. 

Kids go to college, people get sick, income fluctuates, you get laid off etc etc.

I doubt if we have the hardness you recorded but yearly preventative maintenance of any system is imperative to longevity.Given the precarious attic location I would definitely review the obvious advantages of an on-demand system.I have also designed a simple fix for the 'cold water sandwiching' issue that plagues the on-demand systems with feed water temperature fluctuations common in colder climates. 

Heating costs every month are around $700 per month.My only concern is the fluctuating costs of oil.Any thoughts?

This is a very generic question, but in general, the answer depends on the property and type of opportunity it presents to an investor.Assuming by security, you mean the market shows consistent appreciation with little volatility compared to other places the investor could deploy their capital, I would argue that either location is somewhat insulated from the fluctuations seen in the macroeconomy.

What are some strategies I could use to protect my investments not only from legal and environmental events but from market fluctuation and retracements?

If you can rent it out with good cash flow relative to your debt it's OK if the equity fluctuates.

How much have others seen the rates fluctuate, and am I doing the right thing by checking rates daily with the lenders before locking in?  

I'm looking for long term tenants, several have stayed over 30 years, so the fluctuations of market value are irrelavent to me except when I'm selling.Bigger Pockets Podcast Guest #82

Or can it fluctuate?