The first problem is determining whether the green discoloration
is caused from the city side, or RV side. If you fill a plastic
bucket with the city water, does it turn green? If not, the problem
is on the other side...from the connection you use, the hose to the
RV, or something in the RV itself. Green water can be a sign of
algae, green mold, or can be the result of
copper oxide and hydrogen ions much like when a copper penny
turns green. Check and clean the connectors. Are there copper pipes
to the RV or in the route the water takes in the RV. If yes, can
these pipes be replaced with PVC piping. If no copper piping, does
the water sit in a reservoir inside the RV. How clean is the
reservoirand what are the typical cleaning recommendations
forreservoirs inside the RV. Note that if mold, you'll need to use
a product that deals with mold. Since mold and cleaning products
for mold are dangerous to health, you might consider replacing
thereservoir--BUT only after investigating the entire route the
water uses. No sense replacing something if the water is picking up
mold or algae from pipes. It might be worthwhile and less expensive
to have an RV Repair shop go over the entire water route to
identify the problem correctly.