[DK on the road]

Things to consider when you are considering your water quality and rinsing your system.

You can get water sampling kits from any number of labs, they will test for E Coliform and bacteria. Follow the instructions carefully or you will get a failure and panic. Example do not touch the inside of the container. We typically burn the end of the discharging fitting for 3 seconds to burn off local contaminants with a torch, I'm not sure how I would do a faucet except with a match? Seal the container and keep cool/refrigerated/with ice until it delivered to the lab. tests are 48-72 hrs. and a follow-up response will come after 7 days.

If you fail
1) injecting above 40PPM may do damage to the internal rubbers in an older system, or any system for that matter. Maybe 20 PPM should be a set point. On a commercial installation, we chlorinate to 100PPM and let soak for at least 24 hrs, preferably 48 hrs.
2) discharging chlorinated water into a septic system is not recommended, as it depletes the natural breakdown of waste in a septic tank. Discharging into a city sewer system isn't allowed but at a private home you can't get caught.
3) Flushing or rinsing a system should be about 3-5 volumes of a tank and piping.
4) Get Chlorine testing tabs from your local pool supply to let you know the PPM you have placed into your system, then to verify its nearly gone. Your typical public water system has 1-2 PPM. We can typically flush to less than 4 PPM in 3-5 volumes rinsed through. Drinking water above 5PPM will rinse you also.

BTW, don't get any chlorinated water on your clothes or skin. If it gets on your cloths, you will be one of the hip kids with frayed holes all over. Ask me how I know...

Good luck, but testing is easier than chlorinating