I had pyeloplasty 6 wks ago for a rt upj obstruction. stent removal was 2 wks ago. i went to er 2 days ago for severe uti sxs, and us showed that i still have a moderate rt hydronephrosis. is this a normal post-op finding or was the surg a failure?

This will depend on how log obstruction was there and exactly what the UA and prior studies showed. Discuss with Dr who knows all of your details.

Yes, because hydronephrosis due to UPJ obstruction is a chronic condition so it will take months for the anatomic resolution and it is not always complete.

No judhement can be made till the infection is treated completely. Suggest you stick with the surgeon for all followup care.