At our fishing camp we have a water well at 210 feet, and septic system on the Texas Gulf Coast. Plumbing from the pressure tank to the house is buried galvanized pipe and above ground 1" PVC exposed to some sunlight. Have for years noted some algae in the PVC pipes whenever I cut a PVC pipe to make additions or repairs. Have no filter or chlorination on the well water. Have been drinking the well water for 20 years with no ill effects.
Two weeks ago, we visited the camp after 22 degree weather the previous week. The cold seemed to dislodge a huge quantity of algae in the PVC pipes. I turned on the pump and noted a broken pvc pipe from the freeze. The broken PVC pipe was attached to a galvanized riser coming from the pressure tank. As the water gushed from the broken pipe, I noted what looked like dark green/black chopped spinach - pieces ranging in size from small flakes to some half the size of a postage stamp.
I fixed the broken pipe and restored water pressure to the house. Within an hour all the shower heads, sink faucets, etc were clogged and no water flowed.
I ran water from a hose bib at the pressure tank into a bucket, and saw no algae flakes so I assume that algae is in the above ground PVC, however there was algae flowing from the broken PVC pipe attached to the galvanized riser coming out of the ground, so maybe the algae is everywhere - hope it is not in the well.
The house is 12 feet up in the air over a slab. Plumbing under the house is clear PEC and I can still see a lot of dark green in the PEC piping, which I assume is more of the algae.
1. I need to get the shower heads and valves unclogged. How do I do this? Put a garden hose on the pipe where the shower head connects and flush backwards?
2. I need to get the algae out of the piping so everything does not get clogged up again. How do I do this. Back flush? Concerned about using chlorine bleach because of the septic system.
3. I probably need some inline screens in the lines that supply the shower heads and faucets that will prevent clogging. Any recommendation here?
4. Maybe I need a whole house filter in the water line that supplies the house. Any recommendation here?

I'd chlorinate the well, flush everything well and paint the exposed PVC with a UV resistant paint.

get your water re-tested after all the work is done.


Best Wishes