They have fallen out escrow twice due to a plumbing issue.

Electrical and plumbing included. 

Had a couple of plumbers come and quote, and the lowest number came in above $20,000.We have very little knowledge about plumbing and are wondering if spending such a fortunate upfront when no serious leakage has been observed is a good idea.

Minor things will go wrong, plumbing, sprinkler heads, maybe a cracked window, appliance, etc.

Wiring is mostly done and plumbing, ready for insulation and everything else........

Also you will want to look at the foundation and plumbing as well.  

All of my experience is in plumbing and construction work.

One had the plumbing recycled. 

I am a young plumbing/HVAC contractor (I don’t own my own company yet) looking for a little advice for what direction or steps I should be taking to break into the GC/property management part of this industry.

This will help you get a better idea of what tile, hardwood, carpet, plumbing fixtures and light fixtures costs for your rehabs.#3 Contact Local Contractors for Labor PricingCall local Subcontractors and get budget pricing for common repairs on your typical rehab project.For example, call a roofer and ask what their average cost per Square of Architectural Asphalt Shingle Roofing would be on a 1,500 sf house, with a 6/12 pitch.Note: Some contractors will be reluctant to share pricing without seeing the property, but tell them you are just looking for a rough budget number you can use on future projects.#4 Compile Your Prices into a Spreadsheet or Estimating SoftwareOnce you start to get a better understanding of Labor and Material costs you will want to store this data into a spreadsheet or software that you can use to help you streamline the estimating process.The Book on Estimating Rehab Costs comes with a spreadsheet that you can use to help you populate your own database of labor pricing and material pricing.