I just moved into a house that has 2 water heaters. The second one was rarely/never used by previous owner and all the hot water that comes from it is smelly. This came up during the inspections but the inspector said it's because the traps of the drain dried out so now we're smelling sewer gases. That idea was a bunch of sewer gas, but I digress.
Other relevant information is that the hot water heater in question is relatively new being part of an addition from less than 10 years ago. All that work was permitted. The house is on municipal water, not a well. I've already turned the temperature setting way up and let water run for a little while which seemed to help a little but it didn't solve the problem and the next time the water comes on it's back to the smell we started with.
Getting back to the point, I've read in a few places about changing the anode but also about putting hydrogen peroxide in the hot water heater tank. I've found guides/videos on flushing the tank. Unfortunately, I can't find anything about how to get the hydrogen peroxide in the hot water tank. Surely they don't mean to cut into the cold water intake and then repatch that up later, do they?