Chlorinating a water heater continuously

[Robert Barr]

I've tried everything possible to cure a hydrogen sulfide problem with my water heater, including replacing the anode with aluminum and strongly chlorinating the entire plumbing system several times.

The only thing that works is chlorinating the water periodically. I do this the only way that makes sense -- by removing the anode and pouring in about a cup of bleach.

This creates two problems. One, of course, is that the concentration of bleach will start off high and drop off gradually as the hot water is used up. So, initially, I'll have water that smells of bleach, and at the end of the period, the water will smell like hydrogen sulfide.

The other problem is that it's an annoyance to have to drain the tank a bit, pull the anode, pour in a measure of bleach, and reattach the anode. Sooner or later, those threads will die.

I've searched for an inline chlorinator, but every search engine combo I've tried pulls up swimming pool information. I can't find any chlorinator that's for a residential water heater (or residential system for that matter).

Any suggestions?

Thanks.

[Speedy Jim]

Had a similar problem. I put a TEE on the Cold inlet with a plug that could be removed. Still a pain... Then I found a laboratory chemical feed pump. These will meter a precise volume under high pressure. Connect pump to the Cold line thru a corrosion-resistant check valve. I have mine chlorinating all the water, but it could just as well feed only the heater. It has been 100% effective in removing odor and slime buildup. A timer running off the well pump decides how long the feed pump runs.

See what you can find on eBay if new pumps are too pricey.

Jim

[Doug Kanter]

Separate questions, to be answered separately, with lots of white space. White space is good.

1) What's the source of the "pollution"?

2) If chlorine works, is it because there's a biological agent at work which is killed by the chlorine? Or, is the chlorine simply changing a non-organic chemical situation?

3) If no organic agent at work, what would be the result of adding a water softening system? In other words, the addition of salt would certainly affect the pH of the water. Would this alleviate the problem in any way? I'm no chemist, but in two other situations (gardening and keeping a fish tank), I've found that chemicals like fungicides or fish medicine (sledge hammers) are not the solution. What comes first is changing the chemical environment in some other way.

4) Is the chlorine simply working as a masking scent, like the crap that's in laundry soaps just to delight the ladies? Are you sure it's actually eliminating the hydrogen sulfide, or just fooling your nose until it runs out?

5) The million dollar question: Have you consulted with your local water authority? If yes, and you got no good answers, did you say to someone "You and I are gonna be close friends until you hook me up with someone who knows what they're talking about"?

[willshak]

From this page, which also mentions chlorinating systems:

Odors from Hot Water Only "Rotten egg" odors from hydrogen sulfide are sometimes only present in hot water. This may indicate a reaction with the magnesium rod in the water heater. Consider either removal or replacement with an aluminum rod as a remedy. Sometimes hot water will have a "sour" smell, similar to the smell of an old damp rag. This happens when, in an effort to save energy or to avoid blending hot and cold water, the thermostat of the water heater is lowered. Odor-causing bacteria live and thrive in warm water and can infest the water heater. This is corrected by returning the thermostat to its recommended temperature, because the odor-causing bacteria are killed at the higher water temperature (at or above 140 degrees). Caution: Be sure the water heater has an operable pressure relief valve before increasing the water temperature. If you want to keep your water heater temperature at a lower setting because scalding from hot water is a concern, each time the odor returns, increase the water temperature for a few hours to kill the odor-causing bacteria. Then flush the very hot water out of the tank and lower the temperature back to the desired level.

[Robert Barr]

Not certain. Problem began almost immediately after installing a Rheem (GE) electric water heater. Not a certain cause/effect, but when the hot water goes south right after replacing the water heater, the connection looks solid.

We had this identical problem (smelly hot water) years ago when the anode rod deteriorated. At that time, we had a new rod installed, and that cured the problem right away.

This time, the problem refuses to die.

I suspect biological, but nothing to base that on. No problem at all with the cold water. Only the heated. Since the cold is OK, I'm guessing that the chlorine is killing bacteria that arose / grew in the tank.

Water softener (Kinetico, works great) was present before & after problem arose.

I'm pretty certain that there's no masking. After the chlorine is diluted to the point that no chlorine smell is present, the water situation is fine for a few weeks. (I don't use a lot of hot water). The smell will return very gradually.

There's about a 4-week cycle there.

No. The main reason I haven't called the city water department is the timing. No trouble until the GE was installed. No trouble with the cold water.

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[pet]

How about installing an activated charcoal filter system on the cold water supply before the heater? I had a similar problem that was exaggerated by the fact that the hot water was use infrequently which gave the water in the tank time to grow bacteria.

[Doug Kanter]

OK. I forgot to ask how old the water heater is. Whatever the case, I'd get in touch with the manufacturer and stick with them like a bad rash until they arrange for the problem to be fixed WITHOUT your having to play with chlorine. They're simple devices, but like everything else we buy, water heaters are not immune to problems from manufacturing shortcuts. The dip tube mess is a prime example.

Call the manufacturer and turn the screws.

[Robert Barr]

Would you have the brand name of the pump? I think what I need are a few key words for a product search.

I've spent a lot of time using search engines, and I have more to learn, but everything I'd pull up is either industrial or swimming pool, like I said.

Even the 'Tee' connection would be a step up. If I can chlorinate on a regular basis, maybe once a week, I could maintain that nice equilibrium where the water doesn't smell like anything at all.

[Speedy Jim]

There's one on eBay now:

It's overkill but should work. It will probably need to run only a few seconds per day; the amount of chlorination is small. Use a dilute mixture.

You can search Grainger's for feed pumps (they're pricey new).

Jim

[Robert Barr]

I love overkill.

That's a pretty formidable looking piece of equipment. Cool. I would plumb one end to a reservoir of some type, and the other to the WH inlet? Would I have to run the tap at the same time? Otherwise, it would just compress against the city supply, wouldn't it?

Is there maybe a page to describe this process? I'm reasonably good at plumbing, and getting a halfway stable chlorine content shouldn't take too much trial & error. It would sure beat pulling the anode every time.

Thanks for the tip!

[Speedy Jim]

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The pump will create enough pressure to overcome city pressure (I think this one was rated at 100 PSI). From the pic, this one looks like a "peristaltic" pump. You might look that up. Might get away without installing a check valve. Have fun!

Jim

[Robert Barr]

Aha! Finally got some useful info from a search engine.

It's a start, anyway.

[Doug Kanter]

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Having the water heater manufacturer fix the problem for free would beat ALL other solutions. Did you call them today?