Systems Q & A
January 1, 2002
Filed under Trailer How To
Hot-Water System Contamination
Q. We own a 1997 Layton 30-foot fifth-wheel with a slideout room. While dry camping in Bishop, California, we encountered trouble with the water system. Although the freshwater tank was full, the water pressure was low and the shower would not operate at all.
Upon returning from our trip, we took our trailer to Richardson RV, where we had purchased it. The technicians found a white, opaque, jelly-like substance all through the water system. They pulled the freshwater tank and cleaned it, blew out the water lines, cleaned the water pump and water heater. We were told to always keep some water in the freshwater tank and that this would prevent the problem from returning.
In January of this year, I pulled the anode rod from the water heater to inspect it for possible replacement, and I was greeted with a sizable amount of the same material described above. It seems that my problem is back. My questions are: What is it? How do I get rid of it? How do I keep it from coming back?
— J. U., Lakewood, California
Q. I’m having a problem with foul water in my water heater and was hoping you might have a solution or could point me in the right direction. I have a 1996 Aljo fifth-wheel with a Suburban water heater and an approximately 40-gallon freshwater tank. We only use the rig about every other month. This past weekend we turned on the hot water, and the water had an incredibly foul odor of rotting eggs. When I opened the water heater drain, the water came out with lumps of clear-to-white gelatinous stuff.
I tried some commercial water freshener and had limited luck. The water was still foul with the gelatinous pieces, although not as bad. I’ve always filled the freshwater tank at home and have used a Systems IV filter, so I don’t think I got a load of bad water. Any advice on how to fix this problem would be appreciated.
— C.G., Via e-mail
A. That rotten-egg smell and the gelatinous crud you’re both experiencing are due to the reaction of sulfates and microorganisms that flourish in a warm-water environment, such as a water heater. The condition is a water problem, not specifically a water heater or plumbing system problem.
Some water has excessive sulfate content along with strains of sulfate-reducing bacteria, which is harmless to your health but grows in stagnant water that’s been depleted of oxygen. Hydrogen sulfate gas production, using a hydrogen ion from the sacrificial anode reaction, is a by-product of the bacteria growth. The problem is worse in softened water containing sodium. The bacteria can be killed with adequate additions of chlorine, which helps eliminate the odor. The bacteria can’t grow in the presence of oxygen, which may be why they aren’t found in the cold water supply. When the water is heated and oxygen is depleted, the bacteria can grow.
The crud and white gelatinous material are sediments and anode deposits. The sacrificial anode equalizes corrosive water action by providing cathodic protection for the tank. Replacement of the anode is recommended when the rod is 75 percent gone. If the water heater is not in use for extended periods, it’s a good idea to remove the anode rod and drain the tank to extend anode life and eliminate the smelly, stale water.
Here’s how to chlorinate and flush the system using common household bleach: With the water heater cool, remove the anode rod or drain plug, drain about half the water from the tank, and replace the plug. A piece of bent wire can be used to fish some extra crud from the heater while the water is draining. Remove the pressure-relief valve; use the opening to add full-strength bleach to the tank at the rate of about 4 ounces for a 6-gallon tank or 6 ounces of bleach for a 10-gallon tank, top the tank off with water through the opening and replace the valve. Use the RV water pump to finish filling the water heater, and let this bleach mixture sit for about an hour.
Next, run the chlorinated water mixture through the hot-water system by opening each faucet until you smell the bleach at the faucet. This allows the mixture to clean the hot-water lines. Now drain the remaining bleach mixture from the tank and lines using the drain plug and low-point winterizing drain valves in the system. This is a good time to install a new anode rod in the water heater. Now fill the water heater using the RV system water pump, and you can also add about quarter-cup of baking soda through the pressure-relief valve hole to help eliminate the bleach odor and taste, let it sit for 15 minutes or so, then purge the hot-water lines and drain the water heater again. Refill the heater with fresh water and it should be ready to go.