My reef is close to the 2 year mark for running on tap water, however my tap water is excellent. No heavy metals, 0 phosphate, 0 nitrate and it's definitely atypical as far as tap water goes. In fact, I wholeheartedly believe that my tap water is the sole reason why my tank has such low parameters. I believe that the added elements in my tap water allow my macro algae to grow enough to keep phosphate and nitrate at 0, in fact I have been dosing potassium nitrate into my tank daily to color up some of my SPS
corals. I have not been able to feed enough food to ever have a rise in nitrite of phosphate ever since I started growing macro algae. I also do not run any filtration media to remove phosphates. But again, I would not expect people to have a similar experience to me.
With the copper and nitrate in your tap water not to mention the probable presence of phosphates it probably wouldn't be a good plan.