[NCSULandscaper]

i had the same problem on a waterfeature, went over the waterfall several times over a period of a month and everytime i missed the small spot where it was leaking, it took a new eye on the site to find the leak. It was a slight depression and a rock where the water was running over ever so slightly and it was losing about 3" per day, at first i thought evaporation but now, it only drops about 1/4-1/2" per day if its hot and windy.