Perform plumbing inspection today there was no red flags that I can see but I did recommend that he changes his gate valve to the shut off on the Watermain. We also did a water quality check and we discovered he has very hard water this is probably why he needs to flush his tankless so often so we went over a few options to change the quality of his water. Customer was interested in halo five so we sent him an estimate for a full home filtration system. Customer is a member of ours for four years so we gave him a great discount on the whole house filtration system. You can see more details of halo5 in estimate. Also you can look at our plumbing inspection notes for more details.