Client called us out due to them hearing a noise they thought coming from the water heater we installed a few months ago. They said they noticed it after taking a shower/running hot water for a little bit. We ran the tub on hot only and the kitchen faucet at the same time to deplete the hot water to make it heat up/run. We were unable to make that noise happen at this time. Advised client to try to record the noise if it happen again in the future and let us know.