Three quotes to drill a new well and they are wildly different — what makes one job cost double the next?

The clause that matters most is what happens on a dry hole or a low-yield well. Some drillers charge full per-foot rates regardless of what they find, some have a stated depth beyond which pricing changes, and a few will move and try a second location under defined terms. That is the difference between a predictable bill and an open-ended one, and it is the question I would ask before price. Get the answer written into the contract rather than agreed on the phone.

A well quote is really four jobs bundled together, and cheap quotes are usually cheap because they only include the first. There is drilling, normally priced per foot; the casing and grouting, also per foot and sometimes quoted separately; the pump, pressure tank, wiring and pressure switch, which is a different trade in some places; and the trench from wellhead to house plus the electrical hookup. Ask every bidder to break out those four and the difference between your quotes will usually explain itself in ten minutes.

Look up your state or county well log database before you talk to anyone else. Most jurisdictions require drillers to file a log for every well, and you can usually see the depth, the yield and the geology for wells near your lot going back decades. Twenty minutes with that told me my area averaged a certain depth and made it obvious which bidder was quoting realistically and which was quoting optimistically to win the job.

Do not forget the costs that arrive after the drilling: permit fees, the water tests that are usually required before the system is signed off, and the treatment equipment that shows up as necessary once you see what is actually in the water. Our well came in fine on quantity and needed iron treatment, which nobody quoted because nobody could have known. Leave a genuine contingency rather than budgeting to the last pound of the drilling quote.