My son, now 9 and SWCAH, used to go to the bathroom so much that we finally did an ultrasound to check his kidneys.  Fortunately they were okay.  He still sometimes wets the bed at night but it is far and few between.  It was so bad at one time that I recorded his intake and output for the day.  He was putting out almost everything he was taking in.  He is a severe salt looser and at the time was on 44 cc’s of sodium chloride at the time (birth until he was about  7 ish).  Because of the frequent urination we slowly took him off the sodium chloride supplement.  It did get better over time but it wasn’t a quick noticeable change.