Hi, My well pump makes a loud bang every time it kicks on. Just about every time we run water. It's a fairly new home. Only 9 years old.

The first thing I would check is the bladder tank. There are several ways to check your tank. It has a air valve on top like a valve on a tire. Push it in, you should not get any water out of that valve at all. Another way is to tap the tank from the bottom up. You will hear a "clunk" on the bottom filled with water, however you should hear a "clang" near the top filled with air. If you have water up to the top the bladder has ruptured and the tank must be replaced. To set the air pressure in a bladder tank, look at the cut-in pressure on your pressure switch. Now drain the line down with the pump off. When there is no more water coming out of the hose bib, set the pressure 2 lbs. below the cut-in pressure. Check it with a tire gage. If your presssure control is set to come on at 20 PSI and go off at 40 PSI then your gage should read 18 PSI.

This could also be "water hammer" caused by air chambers that have loaded up with water and condensate and need recharging. Back in the 60's we were required to to put shock absorbers,(air chambers) on all bath lavatorys and kitchen sinks. Over time water and condensate built up in them and they must be recharged. First turn off the house at the main house shut off valve. Then open hot and cold faucets at the farthest bathroom to prevent air lock.(This is important.) You will find under each fixture little brass or chrome valves. These are called angle stops. With a small pail held under the angle stop to catch the run off look under the handle of the stop and you will see a nut with the stem running through it. This is called the bonnet packing nut. Put your wrench on it and back it off counterclockwise. Now open the stop and remove the stem and washer assembly, The stop will begain to drain. When it has quit draining reassemble the stop and move on to the next one. Do this on each one of your angle stops. There will be six of them. When you are done, close off the faucets you have opened, turn on the water to the house, and give yourself a pat on the back.
You have just recharged your air chambers and saved yourself a hefty service call bill. Good luck, Tom