I live on a private well and have had a tank for a while. Every few months I'd have to chlorinate the tank (with hydrogen peroxide) to get rid of the rotten egg smell.
Two local plumbing companies advised that the smell was caused by sulfate-reducing bacteria, confirmed by numerous online sources.
I could get rid of it by draining a gallon out of the tank, opening the temp & pressure relief valve, pouring hydrogen peroxide into the tank, and letting this solution flush through the pipes and sit for a few hours.
About a month ago I noticed the smell again and was planning to chlorinate the system. Unfortunately shortly after, the tank was leaking, so I replaced it and "upgraded" to a tankless system.
Now the problem is, after a month, the water still smells. Obviously there is no more anode rod or sitting water, so there must be bacteria still in my pipes. It's mainly coming from one faucet in the kitchen.
How can I flush that pipe, or kill the bacteria in some other way?
Odor in the cold water that goes away after water flows… the most likely source of the hydrogen sulfide is Sulfate-Reducing Bacteria 1
Best Answer
Well, the standard method of chlorinating well systems to kill bacteria in the pipes is to use chlorine (peroxide is an oxidizer, but it's not "chlorinating" in my vocabulary) in the well, and pump it throughout the system, wait several hours, and then flush it out.
Presumably you could use peroxide if you have a sufficient amount, but it's likely to be more expensive than using chlorine bleach (plain, unscented as I would hope would be obvious.)
Interestingly, "overkill" generally is less effective at killing things that a proper level of chorine. My particular well with 200 feet of 6" well full of water above the pump takes about 3 quarts of household bleach. Process is to open the well head, run a hose to the well head and turn it on, and add bleach with the hose running so it gets circulated. Once the chlorine is well-mixed in the well, run water from each tap until you smell the chlorine, then shut it off. Wait several hours, pump most of the chlorinated water out with the hose to somewhere that isn't your septic system or a body of water (run it onto the ground), then flush the pipes in the house once there's no more smell of chlorine from the hose.
I'll go look for references and edit.
http://www.dep.pa.gov/About/Documents/Disinfection%20of%20Home%20Wells%20and%20Springs.pdf
http://www.ct.gov/dph/lib/dph/drinking_water/pdf/Well_Disinfection.pdf
This publication suggests a smaller dose and longer contact time:
http://www.oregon.gov/oha/ph/HealthyEnvironments/DrinkingWater/Operations/Treatment/Documents/CT.pdf