The broker sent us the loan commitment letter to sign but the language in there indicated it was “variable” - I of course questioned that but it took him (no joke) 3 weeks to answer the question of if it’s in fact variable or fixed.

We understand there are a lot of variables in this deal, but this just seems to good to be true if we can get seller on board. 

It is a variable expense that you have no control over and most people are fine paying for what they use if that is common practice in your area. 

Again, there are a lot of unknown variables but it is an attempt.

A region's population and job growth is a great initial indicator to look at as a first step, but then you need to drill down deeper by examining other local variables such as HHIs, GMPs, diversity of economy and other factors that will provide perspective on the vitality of the area's economy.  

@Kyle ThompsonSo many variables.

HELOCs are variable and rates have been uptrending, making these expensive on a monthly basis. 

There are many variables with heavy renovations.

Based on the numbers I am running off the above, you are looking at less than a $10K profit on the flip (57% CoC ROI vs 7% CoC ROI holding post refi (interest rate and how much you are borrowing are big variables).I think you are making the right call and I wouldn't touch the sewer but budget "walk away money" to give in credits at time of sale on the flip.

HELOCs have variable rates, but can be utilized and paid off repeatedly.