Thanks for the advice- I think I will get it tested again by an independent. BTW, The county folks did not even come out. They just sponsored this free weekend of well water testing and you brought down a water sample to them and left it.
I see now that the boiler drain is on a T on the drop pipe so you can't use that.
Caution, Coliform bacteria comes and goes, so doing another test may or may not show a contamination but, usually once a well has shown the presence of Coliform, you shouldn't think you can shock the well and get rid of the problem.
I have personally tested a couple thousand wells for Coliform and shocked hundreds that came back 'positive' or were found to be over the CFU (colony forming unit) allowed (which is < 1 cfu/100 ml) or shown to have E-Coli contamination, including my own.
You're getting some advice here from people with no experience in this but, if you want to do another test, which is silly in my opinion because the county usually isn't going to screw up a test or its result or lie. And I doubt you stuck your finger inside a sterile bag or capped container. The county will write down your address though and keep a record of this, which I do not think is a good thing. And that recording is more what they are after than to help you but, now you know.
You should be able to take a water sample from any sink type fixture in your house and have a no Coliform result.
I do think you need to pull the pump/drop pipe up out of the well to introduce the chlorine. If it was mine I'd get rid of all the galvanized pipe and fittings too. And I'd go a pitless fitting IF you are in a freeze area. Galvanized does not get along well with chlorine and galvanized that is rusted give bacteria a great foothold to breed. Along with adding iron and rust to your water. The stuff should be outlawed for potable water use.
Assuming a submersible pump, I'd use 160 psi rated PE pipe unless you are going down over 450', then I'd use 200 psi; both with extended length insert SS or brass fittings. Either way 1" down to 500' with a 1.5 hp pump. If a jet pump 125 psi and regular sch 80 PVC fittings is fine.
The amount of bleach is critical. Usually a gallon of 5.25% regular nonscented bleach per 100' of water in a 6" well. Bypass any water softener and remove all filter cartridges from housings and shut off the feed water to an RO. *****After getting chlorinated water out of the well through the house for a few minutes, bypass a backwashed carbon filter but not iron etc. filters.
Run a garden hose out to the well. Dilute the bleach into water in buckets and pour it down the well. Stick the hose down the well 10-20' and let it run full open for 20-30 minutes and shut it off. Then run water at every cold water fixture and tap in/outside the house until you can smell bleach in a large container at each cold water faucet, Then turn on washing machines to fill for a minute and shut it off. When done with the cold, run hot water for 3-4 minutes at one faucet and shut it off. Set the temp on the heater to 140f for a few hours and that kills all bacteria.
Then *** bypass a carbon filter and wait 15-20 minutes and run each cold water faucet for 10-15 seconds shut it off and go do the next. When all have been done, repeat that every 15-20 minutes for two to three hours.
This water will spot all clothing and you should keep it out of your eyes and no one should ingest it in anyway. Send all kids somewhere off site and tell them you'll call when they can come home.
At the beginning, expect your water to be very dirty and you might have to take faucet tip aerators off but, you want to smell a strong smell of bleach at all the cold water inside and outside faucets the first time you run them. As time goes by it will decrease and the water may be clear to start and get dirtier or cleaner.
Bleach is heavier than water and it will fall to the bottom of the well, that's why you need to run the hose for that 20-30 minutes, don't shorten or lengthen that time. Bleach weakens when the water is aerated and the idea is to keep pulling strong bleach out of the well to each faucet to replace the used up bleach so you get a full 'kill'. Letting the bleach sit for hours or days weakens it and it doesn't do much more than smell bad and cause things to corrode.
After the 2 hrs or more of the 10-15 minute water runs, pull the hose out of the well and run water somewhere where you don't mind rusty chlorinated water that will probably kill vegetation and stain things. You do not want to run more gpm than the pump can keep up with or to run the well dry, so set the gpm at like 5 gpm and pay strict attention that the water doesn't stop or reduce to a trickle. If it does, shut off the hose for 30 minutes and start it again. The idea is to pump out all the chlorinated water.
When done, sanitize any water softener by using a 1/3 cup of bleach in a couple gals of water poured into the water in the salt tank and do a manual regeneration.
Then 7 to 10 days after there has been no smell of bleach in your water anywhere in the house, take a sample for another Coliform test. Don't be surprised if it comes back as contaminated. If not, retest in 6 month periods from now on as all people with a well should be doing anyway.
Shocking a well can cause pump, power cable, drop pipe and water quality problems that are expensive to fix and if it is a water quality problem like colloidal iron, impossible to fix.
Repeated shocking can make a bacteria problem worse and causing well cleaning and/or rehabilitation to be needed. It can be real tough to impossible to find anyone to do that and most drillers will want to drill a new (read expensive) well for ya instead. Which won't have any guarantee as to the water quality you would get.