I was detecting the water at a local lake on Mon. As I was getting ready to leave a young man came up to me and ask if I would look for his wallet that he dropped off a fishing dock into 4-5' of water? I ask him if there was any metal in his wallet. He said there was a metal emblem on the wallet with an attachment hook. He said he would give me $10.00. I told him I would look for it for free. I went to the dock and jumped into chest deep water in the dark. My ATP would sound off every time I moved the coil. I would scopp and get a load of driftwood and metal junk. I looked for approx. 20 min. I told him my detector was useless with all of the junk in the water.I told him to wait until morning and the water would be clear and he could probably see his wallet. I told him I would bring my scuba gear in the morning and hunt for it if he hadn't found it. I went back on Tues. morning and performed a visual but although there was good visibility I didn't see it. I went to the cabin where he was staying and his father told me he and his son had looked for the wallet that morning with no luck. I put on my scuba mask and started griding the area where he dropped it. No wallet. I remember while I was hunting yesterday that there was a lot of boat traffic and they were kicking up alot of wake that was causing waves to crash on the shoreline. I searched under the dock and went to the opposite side and started gridding. I got out about 30' from parallel to the dock and saw his wallet in 3' of water. I retrieved it and noticed there were a lot of cards and several large denomination bills sticking out of it. I got his Dads attention on the dock and handed him the wallet, he was very happy. He offer me money and I said no, I was glad I could help him and would hope if faced with similar circumstances someone would help me. I told him that I hoped it helped them to end their vacation on a good note. He thanked me and I went back to detecting another area of the lake. I found .35 cents in clad but I was happy about my finds that day.