What makes fresh COLD water in 1 of 3 sinks smell like sewage?
ANSWER: Hi Barbara, I am assuming that this smell is coming from the fresh water regardless if you are using your RV's fresh water tank or are hooked up to city water.
Even though you are getting this smell in only one of your sinks the first thing I am going to suggest is that you freshen up your RV's fresh water system. All you need is about 1/2 gallon of common household bleach, a funnel and your RV's drinking water hose.
The freshening up process is quite simple and straight forward. As they say a picture is worth a 1000 words or in this case a video is worth a 1000 words. In the short video below RVing Expert Mark Polk walks you through the process of sanitizing your RV's fresh water system.
If after you have completed the sanitation process you still get that bad smell at the same sink, it may not be the fresh water you are smelling it could be fumes from your RVs grey water tank.
You may have a vent under your sink known as an Air Admittance Valve (also know as a "Cheater Valve") (pictured above) which is used in
some RVs and Mobile Homes to help speed up sink drainage in areas where a roof drain vent is not feasible.
When you drain water out of your RV's sink the draining water creates suction (vacuum effect) on the valve which then opens and allows air in the pipe which in turn allows the water to drain freely. When the water is done draining the valve is suppose to close tightly and seal out any sewer smell or in your case gray water smell from coming in the RV.
You could have one of these vents on both your kitchen and bathroom sink in your RV. If your sink has an Air Admittance Valve (cheater vent), you should check to make sure that the valve is closing properly if not you need to replace it. The vent is easy to install since it just screws on to a plastic pipe. The hard part is getting to the vent under your kitchen and/or bathroom sink.
Take a look at the video below for even more information on RV air admittance valves (cheater vents)
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